debconf: Perl may be unconfigured (Can't locate strict.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 ...

If you are experiencing troubles with a Ubuntu development version, please report them as a bug against the package related to the issue.
Ubuntu alpha and beta versions are for developers and they are expected to contain bugs, which will then be removed until the release version.
If you are a developer you can assist with good detailed bug reports. If you are an enduser who wants to have a stable system, please use a recent release version, e.g. 13.04 or 12.04 LTS.

In addition to what Thkrueger already told about using a development release:

1. I have shortened the question title to avoid that it spoils the columns

2. The file strict.pm should be supplied by perl-base. So maybe reinstalling that package helps
sudo apt-get install --reinstall perl-base

Hi, Manfred, thanks for taking a look at my problem. I know that what thkrueger said is true, but nevertheless I would like to try to recover my system.

I've tried to reinstall perl-base but it didn't work and I'm caught in loop, because I'm unable to reinstall either python3-software-properties, software-properties-common or software-properties-gtk. Everything I try leads me to the following:

Errors were encountered while processing:
/var/cache/apt/archives/software-properties-common_0.92.25_all.db
/var/cache/apt/archives/python3-software-properties_0.92.25_all.db
/var/cache/apt/archives/software-properties-gtk_0.92.25_all.db
E: Sub-process /usr/bin/dpkg returned an error code (1)

Is there really no way to reinstall those three packages?

Please provide the full error messages of your attempts to reinstall perl-base, software-properties-common etc.

Just telling "it did not work" does not help at all.

You're right, Manfred, my bad. But truth is desktop environment is completed messed up and I navigate through a bunch of unreadable characters just by guessing.

~$ sudo apt-get install --reinstall perl-base

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  python3-software-properties software-properties-common software-properties-gtk
The following packages will be upgraded:
  python3-software-properties software-properties-common software-properties-gtk
3 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
7 not fully installed or removed.
Need to get 0 B/83,6 kB of archives.
After this operation, 0 B of additional disk space will be used.
Do you want to continue [Y/n]? Y
E: Internal Error, No file name for perl-base:i386

~$ sudo apt-get install --reinstall python3-software-properties

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  software-properties-common software-properties-gtk
The following packages will be upgraded:
  python3-software-properties software-properties-common software-properties-gtk
3 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
7 not fully installed or removed.
Need to get 0 B/83,6 kB of archives.
After this operation, 0 B of additional disk space will be used.
Do you want to continue [Y/n]? Y
debconf: Perl may be unconfigured (Can't locate Debconf/Log.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at (eval 1) line 4.
BEGIN failed--compilation aborted at (eval 1) line 4.
) -- aborting
Setting up perl-base (5.14.2-21build1) ...
(Reading database ... 145204 files and directories currently installed.)
Preparing to replace software-properties-common 0.92.24 (using .../software-properties-common_0.92.25_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: error processing /var/cache/apt/archives/software-properties-common_0.92.25_all.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
Traceback (most recent call last):
  File "/usr/bin/py3compile", line 34, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
ImportError: No module named 'debpython'
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 1
Preparing to replace python3-software-properties 0.92.24 (using .../python3-software-properties_0.92.25_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: error processing /var/cache/apt/archives/python3-software-properties_0.92.25_all.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
Traceback (most recent call last):
  File "/usr/bin/py3compile", line 34, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
ImportError: No module named 'debpython'
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 1
Preparing to replace software-properties-gtk 0.92.24 (using .../software-properties-gtk_0.92.25_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: error processing /var/cache/apt/archives/software-properties-gtk_0.92.25_all.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
Traceback (most recent call last):
  File "/usr/bin/py3compile", line 34, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
ImportError: No module named 'debpython'
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/software-properties-common_0.92.25_all.deb
 /var/cache/apt/archives/python3-software-properties_0.92.25_all.deb
 /var/cache/apt/archives/software-properties-gtk_0.92.25_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

The error message is caused by py3compile and py3clean that stem from the package python3.

Maybe reinstalling that package first helps.

No dice.

~$ sudo apt-get install --reinstall python3

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  python3-software-properties software-properties-common software-properties-gtk
The following packages will be upgraded:
  python3-software-properties software-properties-common software-properties-gtk
3 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
6 not fully installed or removed.
Need to get 50,3 kB/134 kB of archives.
After this operation, 0 B of additional disk space will be used.
Do you want to continue [Y/n]? Y
Get:1 http://pt.archive.ubuntu.com/ubuntu/ saucy/main python3 i386 3.3.1-0ubuntu1 [50,3 kB]
Fetched 50,3 kB in 1s (40,5 kB/s)
debconf: Perl may be unconfigured (Can't locate Debconf/Log.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at (eval 1) line 4.
BEGIN failed--compilation aborted at (eval 1) line 4.
) -- aborting
(Reading database ... 145204 files and directories currently installed.)
Preparing to replace software-properties-common 0.92.24 (using .../software-properties-common_0.92.25_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: error processing /var/cache/apt/archives/software-properties-common_0.92.25_all.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
Traceback (most recent call last):
  File "/usr/bin/py3compile", line 34, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
ImportError: No module named 'debpython'
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 1
Preparing to replace python3-software-properties 0.92.24 (using .../python3-software-properties_0.92.25_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: error processing /var/cache/apt/archives/python3-software-properties_0.92.25_all.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
Traceback (most recent call last):
  File "/usr/bin/py3compile", line 34, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
ImportError: No module named 'debpython'
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 1
Preparing to replace software-properties-gtk 0.92.24 (using .../software-properties-gtk_0.92.25_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: error processing /var/cache/apt/archives/software-properties-gtk_0.92.25_all.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
Traceback (most recent call last):
  File "/usr/bin/py3compile", line 34, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
ImportError: No module named 'debpython'
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 1
Preparing to replace python3 3.3.1-0ubuntu1 (using .../python3_3.3.1-0ubuntu1_i386.deb) ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/py3clean", line 32, in <module>
    from debpython import files as dpf
ImportError: No module named 'debpython'
dpkg: error processing /var/cache/apt/archives/python3_3.3.1-0ubuntu1_i386.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
No apport report written because MaxReports is reached already
                                                              Traceback (most recent call last):
  File "/usr/bin/py3compile", line 34, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
ImportError: No module named 'debpython'
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/software-properties-common_0.92.25_all.deb
 /var/cache/apt/archives/python3-software-properties_0.92.25_all.deb
 /var/cache/apt/archives/software-properties-gtk_0.92.25_all.deb
 /var/cache/apt/archives/python3_3.3.1-0ubuntu1_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Also, I've tried to purge those three packages: software-properties-common, python3-software-properties and software-properties-gtk, but even at that I was unable to succeed, still getting the same errors.

Any other ideas, Manfred?

The system seems in a state that you have to apply dirty tricks (that of course have the potential of making things worse):

provide the output of the following commands:

df -h
df -i
/usr/share/python3/debpython

Then try this:

sudo rm /usr/bin/py3clean
sudo dpkg -i /var/cache/apt/archives/python3_3.3.1-0ubuntu1_i386.deb

oops typo error

df -h
df -i
ls -l /usr/share/python3/debpython

~$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 51G 6,8G 42G 15% /
none 4,0K 0 4,0K 0% /sys/fs/cgroup
udev 482M 4,0K 482M 1% /dev
tmpfs 98M 872K 97M 1% /run
none 5,0M 0 5,0M 0% /run/lock
none 490M 208K 489M 1% /run/shm
none 100M 8,0K 100M 1% /run/user
/dev/sda2 46G 132M 44G 1% /home

~$ df -i
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/sda1 3383296 251952 3131344 8% /
none 125227 2 125225 1% /sys/fs/cgroup
udev 123180 463 122717 1% /dev
tmpfs 125227 409 124818 1% /run
none 125227 3 125224 1% /run/lock
none 125227 6 125221 1% /run/shm
none 125227 18 125209 1% /run/user
/dev/sda2 3055616 1929 3053687 1% /home

~$ ls -l /usr/share/python3/debpython
ls: cannot access /usr/share/python3/debpython: No such file or directory

~$ sudo rm /usr/bin/py3clean
~$

~$ sudo dpkg -i /var/cache/apt/archives/python3_3.3.1-0ubuntu1_i386.deb

(Reading database ... 145204 files and directories currently installed.)
Preparing to replace python3 3.3.1-0ubuntu1 (using .../python3_3.3.1-0ubuntu1_i386.deb) ...
running python pre-rtupdate hooks for python3.3...
Unpacking replacement python3 ...
Setting up python3 (3.3.1-0ubuntu1) ...
running python rtupdate hooks for python3.3...
running python post-rtupdate hooks for python3.3...

Hanging on you :)

Looks as if python 3 is reinstalled successfully.

Now check if the debpython directory is there

 ls -l /usr/share/python3/debpython

and if it is there, try reinstalling the three software-properties packages

and finally do
sudo dpkg --audit
sudo dpkg --configure -a
sudo apt-get -f install

please copy/paste all output as done before.

:=) Yes it is, now.

~$ ls -l /usr/share/python3/debpython
total 88
drwxr-xr-x 3 root root 4096 Jul 31 17:27 build
-rw-r--r-- 1 root root 8596 Abr 7 20:33 debhelper.py
-rw-r--r-- 1 root root 7711 Abr 7 20:33 depends.py
-rw-r--r-- 1 root root 3285 Abr 7 20:33 files.py
-rw-r--r-- 1 root root 0 Abr 7 20:33 __init__.py
-rw-r--r-- 1 root root 13517 Abr 7 20:33 interpreter.py
-rw-r--r-- 1 root root 1886 Abr 7 20:33 option.py
drwxr-xr-x 2 root root 4096 Jul 31 17:27 __pycache__
-rw-r--r-- 1 root root 9584 Abr 7 20:33 pydist.py
-rw-r--r-- 1 root root 6969 Abr 7 20:33 tools.py
-rw-r--r-- 1 root root 14794 Abr 7 20:33 version.py

~$ sudo dpkg --audit

The following packages are only half configured, probably due to problems
configuring them the first time. The configuration should be retried using
dpkg --configure <package> or the configure menu option in dselect:
 man-db on-line manual pager
 software-center Utility for browsing, installing, and removing software
 lightdm Display Manager

~$ sudo dpkg --configure -a

Setting up man-db (2.6.5-2) ...
Can't locate Debconf/Db.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/debconf/frontend line 6.
BEGIN failed--compilation aborted at /usr/share/debconf/frontend line 6.
dpkg: error processing man-db (--configure):
 subprocess installed post-installation script returned error exit status 2
Setting up software-center (13.07-0ubuntu4) ...
Traceback (most recent call last):
  File "/usr/bin/pycompile", line 35, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
ImportError: No module named debpython.version
dpkg: error processing software-center (--configure):
 subprocess installed post-installation script returned error exit status 1
Setting up lightdm (1.7.9-0ubuntu1) ...
Can't locate Debconf/Db.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/debconf/frontend line 6.
BEGIN failed--compilation aborted at /usr/share/debconf/frontend line 6.
dpkg: error processing lightdm (--configure):
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 man-db
 software-center
 lightdm

~$ sudo apt-get -f install

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
3 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
debconf: Perl may be unconfigured (Can't locate Debconf/Log.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at (eval 1) line 4.
BEGIN failed--compilation aborted at (eval 1) line 4.
) -- aborting
Setting up man-db (2.6.5-2) ...
Can't locate Debconf/Db.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/debconf/frontend line 6.
BEGIN failed--compilation aborted at /usr/share/debconf/frontend line 6.
dpkg: error processing man-db (--configure):
 subprocess installed post-installation script returned error exit status 2
Setting up lightdm (1.7.9-0ubuntu1) ...
Can't locate Debconf/Db.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/debconf/frontend line 6.
BEGIN failed--compilation aborted at /usr/share/debconf/frontend line 6.
dpkg: error processing lightdm (--configure):
 subprocess installed post-installation script returned error exit status 2
Setting up software-center (13.07-0ubuntu4) ...
Traceback (most recent call last):
  File "/usr/bin/pycompile", line 35, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
ImportError: No module named debpython.version
dpkg: error processing software-center (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 man-db
 lightdm
 software-center
E: Sub-process /usr/bin/dpkg returned an error code (1)

Well, at least the issues with python3-software-properties, software-properties-common or software-properties-gtk, disappeared. Now it's with man-db, lightdm and software-center :(

/usr/share/perl5/Debconf/Db.pm is contained in debconf, so maybe reinstalling that one helps with man-db and lightdm

Why there is an error message
Traceback (most recent call last):
  File "/usr/bin/pycompile", line 35, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr
I do not know, since the ls command shows that version.py exists in /usr/share/python3/debpython

Just try reinstalling debconf
and again
sudo dpkg --audit
sudo dpkg --configure -a
sudo apt-get -f install

~$ sudo apt-get install --reinstall debconf

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
3 not fully installed or removed.
Need to get 149 kB of archives.
After this operation, 0 B of additional disk space will be used.
Get:1 http://pt.archive.ubuntu.com/ubuntu/ saucy/main debconf all 1.5.50ubuntu1 [149 kB]
Fetched 149 kB in 1s (138 kB/s)
debconf: Perl may be unconfigured (Can't locate Debconf/Log.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at (eval 1) line 4.
BEGIN failed--compilation aborted at (eval 1) line 4.
) -- aborting
(Reading database ... 145204 files and directories currently installed.)
Preparing to replace debconf 1.5.50ubuntu1 (using .../debconf_1.5.50ubuntu1_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/pyclean", line 31, in <module>
    from debpython import files as dpf
ImportError: No module named debpython
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/pyclean", line 31, in <module>
    from debpython import files as dpf
ImportError: No module named debpython
dpkg: error processing /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
Can't locate Debconf/Db.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/debconf/frontend line 6.
BEGIN failed--compilation aborted at /usr/share/debconf/frontend line 6.
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

As there were several errors reinstalling debconf, I didn't run the other commands. Do you think that debconf issue it's fixable?

Now I am very astonished as the problem with py3compile pops up again which I thought solved.

I have to stop for today, just some more ideas how to go on (without knowing if that weill lead anywhere):

try reinstalling perl-base again

try reinstalling python3, maybe that needs delete py3clean first

or try

sudo updatedb
locate Db.pm

to check if the Debconf/Db.pm file is really there

Whenever a file name is mentioned, try finding the package that delivers it (with dpkg -S or via search on http://packages.ubuntu.com) and reinstall that package.

~$ sudo apt-get install --reinstall perl-base

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
4 not fully installed or removed.
Need to get 0 B/1614 kB of archives.
After this operation, 0 B of additional disk space will be used.
debconf: Perl may be unconfigured (Can't locate Debconf/Log.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at (eval 1) line 4.
BEGIN failed--compilation aborted at (eval 1) line 4.
) -- aborting
dpkg: error processing debconf (--configure):
 Package is in a very bad inconsistent state - you should
 reinstall it before attempting configuration.
Errors were encountered while processing:
 debconf
E: Sub-process /usr/bin/dpkg returned an error code (1)

~$ sudo rm /usr/bin/py3clean
~$
~$ sudo dpkg -i /var/cache/apt/archives/python3_3.3.1-0ubuntu1_i386.deb
(Reading database ... 145204 files and directories currently installed.)
Preparing to replace python3 3.3.1-0ubuntu1 (using .../python3_3.3.1-0ubuntu1_i386.deb) ...
running python pre-rtupdate hooks for python3.3...
Unpacking replacement python3 ...
Setting up python3 (3.3.1-0ubuntu1) ...
running python rtupdate hooks for python3.3...
running python post-rtupdate hooks for python3.3...

~$ sudo updatedb
~$ locate Db.pm
~$

~$ dpkg -S Db.pm
debconf: /usr/share/perl5/Debconf/Db.pm

~$ sudo apt-get install --reinstall debconf

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
4 not fully installed or removed.
Need to get 0 B/149 kB of archives.
After this operation, 0 B of additional disk space will be used.
debconf: Perl may be unconfigured (Can't locate Debconf/Log.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at (eval 1) line 4.
BEGIN failed--compilation aborted at (eval 1) line 4.
) -- aborting
(Reading database ... 145204 files and directories currently installed.)
Preparing to replace debconf 1.5.50ubuntu1 (using .../debconf_1.5.50ubuntu1_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/pyclean", line 31, in <module>
    from debpython import files as dpf
ImportError: No module named debpython
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/pyclean", line 31, in <module>
    from debpython import files as dpf
ImportError: No module named debpython
dpkg: error processing /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
Can't locate Debconf/Db.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/debconf/frontend line 6.
BEGIN failed--compilation aborted at /usr/share/debconf/frontend line 6.
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

No problem, Manfred. I'll wait for you, and for some more ideas how to go on, until tomorrow, if you don't mind.
Thanks for all your help.

I would like to recommend that you perform a file system check on your file systems.

Issue the commands

sudo touch /forcefsck
sudo reboot

and carefully check for error messages at the next booting.

Well, the system rebooted and performed the file system check, but it didn't post any errors.

Ok. Let me summarize:
There are error messages when you try installing/removing/updating packages, among them

Traceback (most recent call last):
  File "/usr/bin/pyclean", line 31, in <module>
    from debpython import files as dpf

Can't locate Debconf/Db.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/debconf/frontend line 6.

I see the following packages as being candidates for being the culprit: debconf, python3, perl-base.

What is the output of the following commands:

sudo dpkg --audit
sudo py3compile -p python3
sudo py3compile -p debconf

~$ sudo dpkg --audit

The following packages are in a mess due to serious problems during
installation. They must be reinstalled for them (and any packages
that depend on them) to function properly:
 debconf Debian configuration management system

The following packages are only half configured, probably due to problems
configuring them the first time. The configuration should be retried using
dpkg --configure <package> or the configure menu option in dselect:
 man-db on-line manual pager
 software-center Utility for browsing, installing, and removing software
 lightdm Display Manager

~$ sudo py3compile -p python3
~$

~$ sudo py3compile -p debconf
~$

Those last two didn't produce any output.

Not producing an output in most cases is a good sign, because it shows that there was no error.

ok, now try the commands

sudo dpkg -i /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb
sudo dpkg -i /var/cache/apt/archives/python3_3.3.1-0ubuntu1_i386.deb
sudo apt-get install --reinstall perl-base

and copy/paste all output as done before.

It's like they say, "No news is good news".
Ok, here they go.

~$ sudo dpkg -i /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb

(Reading database ... 145204 files and directories currently installed.)
Preparing to replace debconf 1.5.50ubuntu1 (using .../debconf_1.5.50ubuntu1_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/pyclean", line 31, in <module>
    from debpython import files as dpf
ImportError: No module named debpython
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/pyclean", line 31, in <module>
    from debpython import files as dpf
ImportError: No module named debpython
dpkg: error processing /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb (--install):
 subprocess new pre-removal script returned error exit status 1
Can't locate Debconf/Db.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/debconf/frontend line 6.
BEGIN failed--compilation aborted at /usr/share/debconf/frontend line 6.
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb

~$ sudo dpkg -i /var/cache/apt/archives/python3_3.3.1-0ubuntu1_i386.deb

(Reading database ... 145204 files and directories currently installed.)
Preparing to replace python3 3.3.1-0ubuntu1 (using .../python3_3.3.1-0ubuntu1_i386.deb) ...
running python pre-rtupdate hooks for python3.3...
Unpacking replacement python3 ...
Setting up python3 (3.3.1-0ubuntu1) ...
running python rtupdate hooks for python3.3...
running python post-rtupdate hooks for python3.3...

~$ sudo apt-get install --reinstall perl-base

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 24 not upgraded.
4 not fully installed or removed.
Need to get 0 B/1614 kB of archives.
After this operation, 0 B of additional disk space will be used.
debconf: Perl may be unconfigured (Can't locate Debconf/Log.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at (eval 1) line 4.
BEGIN failed--compilation aborted at (eval 1) line 4.
) -- aborting
dpkg: error processing debconf (--configure):
 Package is in a very bad inconsistent state - you should
 reinstall it before attempting configuration.
No apport report written because MaxReports is reached already
                                                              Errors were encountered while processing:
 debconf
E: Sub-process /usr/bin/dpkg returned an error code (1)

The only one that went ok was the Pyhton one.

Might be that I was focusing on the wrong python package, try reinstalling python and python-minimal (not python3).

~$ sudo apt-get install --reinstall python

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 24 not upgraded.
4 not fully installed or removed.
Need to get 0 B/318 kB of archives.
After this operation, 0 B of additional disk space will be used.
debconf: Perl may be unconfigured (Can't locate Debconf/Log.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at (eval 1) line 4.
BEGIN failed--compilation aborted at (eval 1) line 4.
) -- aborting
dpkg: error processing debconf (--configure):
 Package is in a very bad inconsistent state - you should
 reinstall it before attempting configuration.
Errors were encountered while processing:
 debconf
E: Sub-process /usr/bin/dpkg returned an error code (1)

~$ sudo apt-get install --reinstall python-minimal
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 24 not upgraded.
4 not fully installed or removed.
Need to get 31,3 kB/180 kB of archives.
After this operation, 0 B of additional disk space will be used.
Get:1 http://pt.archive.ubuntu.com/ubuntu/ saucy/main python-minimal i386 2.7.5-1ubuntu1 [31,3 kB]
Fetched 31,3 kB in 1s (18,1 kB/s)
debconf: Perl may be unconfigured (Can't locate Debconf/Log.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at (eval 1) line 4.
BEGIN failed--compilation aborted at (eval 1) line 4.
) -- aborting
dpkg: error processing debconf (--configure):
 Package is in a very bad inconsistent state - you should
 reinstall it before attempting configuration.
Errors were encountered while processing:
 debconf
E: Sub-process /usr/bin/dpkg returned an error code (1)

:(

Now try installing all failing packages, but with dpkg and not with apt-get

sudo dpkg -i /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb
sudo dpkg -i /var/cache/apt/archives/python-minimal_2.7.5-1ubuntu1_i386.deb

:~$ sudo dpkg -i /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb

(Reading database ... 145204 files and directories currently installed.)
Preparing to replace debconf 1.5.50ubuntu1 (using .../debconf_1.5.50ubuntu1_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/pyclean", line 31, in <module>
    from debpython import files as dpf
ImportError: No module named debpython
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
Traceback (most recent call last):
  File "/usr/bin/pyclean", line 31, in <module>
    from debpython import files as dpf
ImportError: No module named debpython
dpkg: error processing /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb (--install):
 subprocess new pre-removal script returned error exit status 1
Can't locate Debconf/Db.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/share/debconf/frontend line 6.
BEGIN failed--compilation aborted at /usr/share/debconf/frontend line 6.
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb

~$ sudo dpkg -i /var/cache/apt/archives/python-minimal_2.7.5-1ubuntu1_i386.deb
[sudo] password for slickymaster:
(Reading database ... 145204 files and directories currently installed.)
Preparing to replace python-minimal 2.7.5-1ubuntu1 (using .../python-minimal_2.7.5-1ubuntu1_i386.deb) ...
Unpacking replacement python-minimal ...
Setting up python-minimal (2.7.5-1ubuntu1) ...

It seems that python-minimal is resolved, but there's still the problem with debconf.

repeat with debconf

Great. Can we claim victory?

~$ sudo dpkg -i /var/cache/apt/archives/debconf_1.5.50ubuntu1_all.deb

(Reading database ... 145204 files and directories currently installed.)
Preparing to replace debconf 1.5.50ubuntu1 (using .../debconf_1.5.50ubuntu1_all.deb) ...
Unpacking replacement debconf ...
Setting up debconf (1.5.50ubuntu1) ...

now try

sudo dpkg --configure -a
sudo apt-get install -f
and if there is still no error
sudo apt--get update

~$ sudo dpkg --configure -a

Setting up man-db (2.6.5-2) ...
Updating database of manual pages ...
Setting up software-center (13.07-0ubuntu4) ...
ERROR:root:DebFileApplication import
Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/db/__init__.py", line 4, in <module>
    from debfile import DebFileApplication, DebFileOpenError
  File "/usr/share/software-center/softwarecenter/db/debfile.py", line 25, in <module>
    from softwarecenter.db.application import Application, AppDetails
  File "/usr/share/software-center/softwarecenter/db/application.py", line 38, in <module>
    from softwarecenter.region import get_region_cached, REGIONTAG
  File "/usr/share/software-center/softwarecenter/region.py", line 21, in <module>
    from dbus.mainloop.glib import DBusGMainLoop
ImportError: No module named mainloop.glib
Traceback (most recent call last):
  File "/usr/sbin/update-software-center", line 38, in <module>
    from softwarecenter.db.update import rebuild_database
  File "/usr/share/software-center/softwarecenter/db/update.py", line 67, in <module>
    from softwarecenter.db.database import parse_axi_values_file
  File "/usr/share/software-center/softwarecenter/db/database.py", line 26, in <module>
    from softwarecenter.db.application import Application
  File "/usr/share/software-center/softwarecenter/db/application.py", line 38, in <module>
    from softwarecenter.region import get_region_cached, REGIONTAG
  File "/usr/share/software-center/softwarecenter/region.py", line 21, in <module>
    from dbus.mainloop.glib import DBusGMainLoop
ImportError: No module named mainloop.glib
Setting up lightdm (1.7.9-0ubuntu1) ...

~$ sudo apt-get install -f
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 24 not upgraded.

~$ sudo apt-get update

Ign http://pt.archive.ubuntu.com saucy InRelease
Ign http://archive.canonical.com saucy InRelease
Ign http://ppa.launchpad.net raring InRelease
Ign http://extras.ubuntu.com saucy InRelease
Ign http://dl.google.com stable InRelease
Ign http://security.ubuntu.com saucy-security InRelease
Ign http://pt.archive.ubuntu.com saucy-updates InRelease
Hit http://security.ubuntu.com saucy-security Release.gpg
Hit http://archive.canonical.com saucy Release.gpg
Get:1 http://extras.ubuntu.com saucy Release.gpg [72 B]
Hit http://dl.google.com stable Release.gpg
Ign http://ppa.launchpad.net saucy InRelease
Hit http://extras.ubuntu.com saucy Release
Ign http://pt.archive.ubuntu.com saucy-backports InRelease
Get:2 http://pt.archive.ubuntu.com saucy Release.gpg [933 B]
Hit http://security.ubuntu.com saucy-security Release
Hit http://archive.canonical.com saucy Release
Hit http://dl.google.com stable Release
Hit http://ppa.launchpad.net raring Release.gpg
Hit http://extras.ubuntu.com saucy/main Sources
Hit http://pt.archive.ubuntu.com saucy-updates Release.gpg
Hit http://pt.archive.ubuntu.com saucy-backports Release.gpg
Ign http://ppa.launchpad.net saucy Release.gpg
Hit http://security.ubuntu.com saucy-security/main Sources
Hit http://extras.ubuntu.com saucy/main i386 Packages
Hit http://archive.canonical.com saucy/partner Sources
Hit http://security.ubuntu.com saucy-security/restricted Sources
Hit http://dl.google.com stable/main i386 Packages
Hit http://archive.canonical.com saucy/partner i386 Packages
Hit http://ppa.launchpad.net raring Release
Hit http://security.ubuntu.com saucy-security/universe Sources
Ign http://ppa.launchpad.net saucy Release
Hit http://security.ubuntu.com saucy-security/multiverse Sources
Hit http://security.ubuntu.com saucy-security/main i386 Packages
Hit http://security.ubuntu.com saucy-security/restricted i386 Packages
Hit http://security.ubuntu.com saucy-security/universe i386 Packages
Hit http://ppa.launchpad.net raring/main Sources
Hit http://security.ubuntu.com saucy-security/multiverse i386 Packages
Hit http://ppa.launchpad.net raring/main i386 Packages
Hit http://security.ubuntu.com saucy-security/main Translation-en
Get:3 http://pt.archive.ubuntu.com saucy Release [40,8 kB]
Hit http://security.ubuntu.com saucy-security/multiverse Translation-en
Ign http://extras.ubuntu.com saucy/main Translation-en_US
Ign http://extras.ubuntu.com saucy/main Translation-en
Hit http://security.ubuntu.com saucy-security/restricted Translation-en
Ign http://dl.google.com stable/main Translation-en_US
Ign http://dl.google.com stable/main Translation-en
Ign http://archive.canonical.com saucy/partner Translation-en_US
Hit http://security.ubuntu.com saucy-security/universe Translation-en
Ign http://archive.canonical.com saucy/partner Translation-en
Hit http://pt.archive.ubuntu.com saucy-updates Release
Hit http://pt.archive.ubuntu.com saucy-backports Release
Get:4 http://pt.archive.ubuntu.com saucy/main Sources [1004 kB]
Ign http://security.ubuntu.com saucy-security/main Translation-en_US
Ign http://security.ubuntu.com saucy-security/multiverse Translation-en_US
Ign http://ppa.launchpad.net raring/main Translation-en_US
Ign http://security.ubuntu.com saucy-security/restricted Translation-en_US
Ign http://ppa.launchpad.net raring/main Translation-en
Err http://ppa.launchpad.net saucy/main Sources
  404 Not Found
Ign http://security.ubuntu.com saucy-security/universe Translation-en_US
Err http://ppa.launchpad.net saucy/main i386 Packages
  404 Not Found
Ign http://ppa.launchpad.net saucy/main Translation-en_US
Ign http://ppa.launchpad.net saucy/main Translation-en
Get:5 http://pt.archive.ubuntu.com saucy/restricted Sources [6588 B]
Get:6 http://pt.archive.ubuntu.com saucy/universe Sources [6076 kB]
Get:7 http://pt.archive.ubuntu.com saucy/multiverse Sources [176 kB]
Get:8 http://pt.archive.ubuntu.com saucy/main i386 Packages [1235 kB]
Get:9 http://pt.archive.ubuntu.com saucy/restricted i386 Packages [9955 B]
Get:10 http://pt.archive.ubuntu.com saucy/universe i386 Packages [5611 kB]
Get:11 http://pt.archive.ubuntu.com saucy/multiverse i386 Packages [134 kB]
Get:12 http://pt.archive.ubuntu.com saucy/main Translation-en [705 kB]
Hit http://pt.archive.ubuntu.com saucy/multiverse Translation-en
Hit http://pt.archive.ubuntu.com saucy/restricted Translation-en
Get:13 http://pt.archive.ubuntu.com saucy/universe Translation-en [3862 kB]
Hit http://pt.archive.ubuntu.com saucy-updates/main Sources
Hit http://pt.archive.ubuntu.com saucy-updates/restricted Sources
Hit http://pt.archive.ubuntu.com saucy-updates/universe Sources
Hit http://pt.archive.ubuntu.com saucy-updates/multiverse Sources
Hit http://pt.archive.ubuntu.com saucy-updates/main i386 Packages
Hit http://pt.archive.ubuntu.com saucy-updates/restricted i386 Packages
Hit http://pt.archive.ubuntu.com saucy-updates/universe i386 Packages
Hit http://pt.archive.ubuntu.com saucy-updates/multiverse i386 Packages
Hit http://pt.archive.ubuntu.com saucy-updates/main Translation-en
Hit http://pt.archive.ubuntu.com saucy-updates/multiverse Translation-en
Hit http://pt.archive.ubuntu.com saucy-updates/restricted Translation-en
Hit http://pt.archive.ubuntu.com saucy-updates/universe Translation-en
Hit http://pt.archive.ubuntu.com saucy-backports/main Sources
Hit http://pt.archive.ubuntu.com saucy-backports/restricted Sources
Hit http://pt.archive.ubuntu.com saucy-backports/universe Sources
Hit http://pt.archive.ubuntu.com saucy-backports/multiverse Sources
Hit http://pt.archive.ubuntu.com saucy-backports/main i386 Packages
Hit http://pt.archive.ubuntu.com saucy-backports/restricted i386 Packages
Hit http://pt.archive.ubuntu.com saucy-backports/universe i386 Packages
Hit http://pt.archive.ubuntu.com saucy-backports/multiverse i386 Packages
Hit http://pt.archive.ubuntu.com saucy-backports/main Translation-en
Hit http://pt.archive.ubuntu.com saucy-backports/multiverse Translation-en
Hit http://pt.archive.ubuntu.com saucy-backports/restricted Translation-en
Hit http://pt.archive.ubuntu.com saucy-backports/universe Translation-en
Ign http://pt.archive.ubuntu.com saucy/main Translation-en_US
Ign http://pt.archive.ubuntu.com saucy/multiverse Translation-en_US
Ign http://pt.archive.ubuntu.com saucy/restricted Translation-en_US
Ign http://pt.archive.ubuntu.com saucy/universe Translation-en_US
Ign http://pt.archive.ubuntu.com saucy-updates/main Translation-en_US
Ign http://pt.archive.ubuntu.com saucy-updates/multiverse Translation-en_US
Ign http://pt.archive.ubuntu.com saucy-updates/restricted Translation-en_US
Ign http://pt.archive.ubuntu.com saucy-updates/universe Translation-en_US
Ign http://pt.archive.ubuntu.com saucy-backports/main Translation-en_US
Ign http://pt.archive.ubuntu.com saucy-backports/multiverse Translation-en_US
Ign http://pt.archive.ubuntu.com saucy-backports/restricted Translation-en_US
Ign http://pt.archive.ubuntu.com saucy-backports/universe Translation-en_US
Fetched 18,9 MB in 7min 24s (42,4 kB/s)
W: Failed to fetch http://ppa.launchpad.net/geany-dev/ppa/ubuntu/dists/saucy/main/source/Sources 404 Not Found

W: Failed to fetch http://ppa.launchpad.net/geany-dev/ppa/ubuntu/dists/saucy/main/binary-i386/Packages 404 Not Found

E: Some index files failed to download. They have been ignored, or old ones used instead.

Besides those Launchpad packages that it wasn't able to fetch, everything seems alright now. Dow you think I can execute sudo apt-get upgrade or should I reboot first?

To get rid of the warning you have to disable the geany-dev ppa. That PPA is not offering software for saucy yet.

And yes, it seems time to do sudo apt-get upgrade, eventually also sudo apt-get dist-upgrade.

Now I'm getting problems with sane-utils :(
And my desktop continuous completed messed up with just unreadable characters

~$ sudo apt-get upgrade

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue [Y/n]? Y
Setting up sane-utils (1.0.23-0ubuntu3) ...
Can't locate DebianNet.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/sbin/update-inetd line 24.
dpkg: error processing sane-utils (--configure):
 subprocess installed post-installation script returned error exit status 2
No apport report written because MaxReports is reached already
                                                              Errors were encountered while processing:
 sane-utils
E: Sub-process /usr/bin/dpkg returned an error code (1)

Try reinstalling update-inetd

~$ sudo apt-get install --reinstall update-inetd

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
Need to get 0 B/19,2 kB of archives.
After this operation, 0 B of additional disk space will be used.
Preconfiguring packages ...
(Reading database ... 145221 files and directories currently installed.)
Preparing to replace update-inetd 4.43 (using .../update-inetd_4.43_all.deb) ...
Unpacking replacement update-inetd ...
Processing triggers for man-db ...
Setting up update-inetd (4.43) ...

~$ sudo apt-get dist-upgrade

Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Everything seems to be fixed besides the fact that I don't have a readable desktop, instead of words I only have symbols. Could it be a problem with xorg or plymouth or even lightdm?

The problem can be that some of the installation scripts were aborted due to problems with python, perl, debconf..., and I am not sure if they all were correctly re-applied afterwards.

You could try re-installing all packages that you have currently installed.

Try the following:

sudo apt-get autoclean
sudo dpkg -i /var/cache/apt/archives/*.deb

No idea if that will help.

Nops. It didn't solve it. What do you recommend, now? Reinstallation? How can I do it preserving my /home partition?

Before you have to do a complete new installation, I would like to recommend to try reinstalling all packages first. This can best be done with a procedure which you have already used in a previous problem https://answers.launchpad.net/ubuntu/+question/227848

dpkg -l | grep ^ii | awk '{print "sudo apt-get install --reinstall --no-install-recommends -y ", $2}' > ~/reinstall
chmod +x ~/reinstall
sh ~/reinstall

Done, Manfred. I'm pasting just the final part of it. Even though my desktop is completely fixed it's now sort of readable, since I already have words mixed the the symbols. And I know the problem now lies down with the xubuntu-desktop package.
So I humbly ask you once again for your advise on what to do next.

(Reading database ... 145224 files and directories currently installed.)
Preparing to replace zlib1g:i386 1:1.2.8.dfsg-1ubuntu1 (using .../zlib1g_1%3a1.2.8.dfsg-1ubuntu1_i386.deb) ...
Unpacking replacement zlib1g:i386 ...
Setting up zlib1g:i386 (1:1.2.8.dfsg-1ubuntu1) ...
Setting up doc-base (0.10.5) ...
Can't locate Debian/DocBase/Common.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/sbin/install-docs line 8.
BEGIN failed--compilation aborted at /usr/sbin/install-docs line 8.
dpkg: error processing doc-base (--configure):
 subprocess installed post-installation script returned error exit status 2
No apport report written because MaxReports is reached already
                                                              dpkg: dependency problems prevent configuration of xubuntu-desktop:
 xubuntu-desktop depends on doc-base; however:
  Package doc-base is not configured yet.

dpkg: error processing xubuntu-desktop (--configure):
 dependency problems - leaving unconfigured
No apport report written because MaxReports is reached already
                                                              Processing triggers for libc-bin ...
Errors were encountered while processing:
 doc-base
 xubuntu-desktop
E: Sub-process /usr/bin/dpkg returned an error code (1)
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
Need to get 181 kB of archives.
After this operation, 0 B of additional disk space will be used.
Get:1 http://pt.archive.ubuntu.com/ubuntu/ saucy/main zlib1g-dev i386 1:1.2.8.dfsg-1ubuntu1 [181 kB]
Fetched 181 kB in 7s (23,1 kB/s)
(Reading database ... 145224 files and directories currently installed.)
Preparing to replace zlib1g-dev:i386 1:1.2.8.dfsg-1ubuntu1 (using .../zlib1g-dev_1%3a1.2.8.dfsg-1ubuntu1_i386.deb) ...
Unpacking replacement zlib1g-dev:i386 ...
Processing triggers for man-db ...
Setting up doc-base (0.10.5) ...
Can't locate Debian/DocBase/Common.pm in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .) at /usr/sbin/install-docs line 8.
BEGIN failed--compilation aborted at /usr/sbin/install-docs line 8.
dpkg: error processing doc-base (--configure):
 subprocess installed post-installation script returned error exit status 2
dpkg: dependency problems prevent configuration of xubuntu-desktop:
 xubuntu-desktop depends on doc-base; however:
  Package doc-base is not configured yet.

dpkg: error processing xubuntu-desktop (--configure):
 dependency problems - leaving unconfigured
Setting up zlib1g-dev:i386 (1:1.2.8.dfsg-1ubuntu1) ...
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          Errors were encountered while processing:
 doc-base
 xubuntu-desktop
E: Sub-process /usr/bin/dpkg returned an error code (1)

Just adding some more information. I rebooted to a non stop series of crashes. From aspell.0, debconf.0, doc-base.0, gconf2.0 and the list goes on.

Despite all your efforts, Manfred, this time it seems that there's no way to succeed. What do you think is the best thing to do?

I do not fully understand your last message: can you boot your system now, or is it impossible to start it?
Can you boot into recovery mode without X GUI?

My ideas for the previous messages would be:

reinstall docbase and check the output.

If there is an error message copy/paste it to this document

If there is no error with docbase, run the reinstall script again

verify if there are any other messages of the form
Can't locate "filename" in @INC (@INC contains: ...

if yes, provide the file named shown in these messages, verify which package provides these, and manually reinstall the related packages.

Sorry Manfred, I may have expressed myself incorrectly. I do boot into my desktop session, that's not the problem, and I do, now, have a readable desktop. Thing is that last Friday, after I had reboot the computer a series of endless crashes. There were so many that Apport itself started to crash because it wasn't able to produce the amount of crash reports he was being solicited.

Strange thing is that today, before I started an X session I run an apt-get update && apt-dist upgrade, and so far I haven't noticed a single crash, but the issue with doc-base and xubuntu-desktop still subsist so I tried to reinstall doc-base. Here's the output:

~$ sudo apt-get install --reinstall doc-base

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
E: Internal Error, No file name for doc-base:i386

You might try
sudo dpkg -i /var/cache/apt/archives/doc-base_0.10.5*.deb

What is the output of
dpkg --audit

:~$ sudo dpkg --audit

The following packages have been unpacked but not yet configured.
They must be configured using dpkg --configure or the configure
menu option in dselect for them to work:
 xubuntu-desktop Xubuntu desktop system

The following packages are only half configured, probably due to problems
configuring them the first time. The configuration should be retried using
dpkg --configure <package> or the configure menu option in dselect:
 doc-base utilities to manage online documentation

~$ sudo dpkg -i /var/cache/apt/archives/doc-base_0.10.5*.deb
dpkg: error processing /var/cache/apt/archives/doc-base_0.10.5*.deb (--install):
 cannot access archive: No such file or directory
Errors were encountered while processing:
 /var/cache/apt/archives/doc-base_0.10.5*.deb

I've also tried:
~$ sudo dpkg --configure xubuntu-desktop
dpkg: dependency problems prevent configuration of xubuntu-desktop:
 xubuntu-desktop depends on doc-base; however:
  Package doc-base is not configured yet.

dpkg: error processing xubuntu-desktop (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 xubuntu-desktop

So the problem now resides in the doc-base itself, which is apparently locking the xubuntu-desktop and Xubuntu desktop system from being properly configured.
But I'm confident that you have a solution to solve the doc-base package issue.

sudo apt-get install --reinstall doc-base
(that will probably fail)
sudo dpkg -i /var/cache/apt/archives/doc-base_0.10.5_all.deb
(if that again fails with 'No such file or directory')
sudo dpkg -i /var/cache/apt/archives/doc-base*.deb

~$ sudo apt-get install --reinstall doc-base

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
E: Internal Error, No file name for doc-base:i386

~$ sudo dpkg -i /var/cache/apt/archives/doc-base_0.10.5_all.deb

dpkg: error processing /var/cache/apt/archives/doc-base_0.10.5_all.deb (--install):
 cannot access archive: No such file or directory
Errors were encountered while processing:
 /var/cache/apt/archives/doc-base_0.10.5_all.deb

~$ sudo dpkg -i /var/cache/apt/archives/doc-base*.deb

dpkg: error processing /var/cache/apt/archives/doc-base*.deb (--install):
 cannot access archive: No such file or directory
Errors were encountered while processing:
 /var/cache/apt/archives/doc-base*.deb

None of them worked.

sudo apt-get install --reinstall -d doc-base
sudo dpkg -i /var/cache/apt/archives/doc-base*.deb

if that again fails, please provide the output of

apt-cache policy doc-base

~$ sudo apt-get install --reinstall -d doc-base
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Download complete and in download only mode

~$ sudo dpkg -i /var/cache/apt/archives/doc-base*.deb
dpkg: error processing /var/cache/apt/archives/doc-base*.deb (--install):
 cannot access archive: No such file or directory
Errors were encountered while processing:
 /var/cache/apt/archives/doc-base*.deb

~$ apt-cache policy doc-base
doc-base:
  Installed: 0.10.5
  Candidate: 0.10.5
  Version table:
 *** 0.10.5 0
        500 http://pt.archive.ubuntu.com/ubuntu/ saucy/main i386 Packages
        100 /var/lib/dpkg/status

In the moment I cannot understand why the .deb file for doc-base is not in the archive directory.

Ok, do it differently:

cd ~
wget -c http://pt.archive.ubuntu.com/ubuntu/pool/main/d/doc-base/doc-base_0.10.5_all.deb
sudo dpkg -i ~/doc-base_0.10.5_all.deb
sudo cp -v ~/doc-base_0.10.5_all.deb /var/cache/apt/archives/
rm ~/doc-base_0.10.5_all.deb
sudo dpkg --configure -a

~$ cd ~
~$ wget -c http://pt.archive.ubuntu.com/ubuntu/pool/main/d/doc-base/doc-base_0.10.5_all.deb
--2013-08-05 12:52:18-- http://pt.archive.ubuntu.com/ubuntu/pool/main/d/doc-base/doc-base_0.10.5_all.deb
Resolving pt.archive.ubuntu.com (pt.archive.ubuntu.com)... 193.136.212.166
Connecting to pt.archive.ubuntu.com (pt.archive.ubuntu.com)|193.136.212.166|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 86068 (84K) [application/x-debian-package]
Saving to: ‘doc-base_0.10.5_all.deb’

100%[======================================>] 86.068 358KB/s in 0,2s

2013-08-05 12:52:20 (358 KB/s) - ‘doc-base_0.10.5_all.deb’ saved [86068/86068]

~$ sudo dpkg -i ~/doc-base_0.10.5_all.deb

(Reading database ... 145271 files and directories currently installed.)
Preparing to replace doc-base 0.10.5 (using .../doc-base_0.10.5_all.deb) ...
Unpacking replacement doc-base ...
Setting up doc-base (0.10.5) ...
Processing 48 changed doc-base files...
Registering documents with scrollkeeper...
Processing triggers for man-db ...

~$ sudo cp -v ~/doc-base_0.10.5_all.deb /var/cache/apt/archives/
‘/home/korrigan/doc-base_0.10.5_all.deb’ -> ‘/var/cache/apt/archives/doc-base_0.10.5_all.deb’
:~$ rm ~/doc-base_0.10.5_all.deb
:~$ sudo dpkg --configure -a
Setting up xubuntu-desktop (2.168) ...
~$

It went smoothly and I believe that xubuntu-desktop is now perfectly configured. Is there anything left to do?

Thanks Manfred Hampl, that solved my question.

Once again Manfred you left completely astonished with the level of know-how you possess, and once again you've turned what seems as a lost system into a perfect and smooth working one.

Finally, and again, I can not translate into words the immense sense of gratitude I rest towards you.

I have to confess that when I open this question I was almost praying for you to be the one who would pick it up.