hplip Hp laserjet P1102 and No devices found on bus: usb

I am using Ubuntu 10.04.
My Printer is HP Laserjet P1102
My hplip is : 3.12.4
The user is in lp group

With lsusb I can see the printer:
Bus 002 Device 006: ID 03f0:002a Hewlett-Packard

After run hplip and hp-plugins,when I type "hp-setup" the GUI HP setup interface appears, but it seems that there are no printers connected via USB even if my printer is powered on and USB connected.
With sudo hp-setup I received:

Copyright (c) 2001-14 Hewlett-Packard Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

Searching... (bus=usb, search=(None), desc=0)
error: No devices found on bus: usb

With hp-check -t I get:

HP Linux Imaging and Printing System (ver. 3.12.4)
Dependency/Version Check Utility ver. 14.3

Saving output in log file: hp-check.log

Initializing. Please wait...

---------------
| SYSTEM INFO |
---------------

Basic system information:
Linux mario-desktop 2.6.32-40-generic #87-Ubuntu SMP Mon Mar 5 20:26:31 UTC 2012 i686 GNU/Linux

Distribution:
ubuntu 10.04

Checking Python version...
OK, version 2.6.5 installed

Checking PyQt 4.x version...
OK, version 4.7.2 installed.

Checking for CUPS...
Status: la stampa programmata è in esecuzione
Version: 1.4.3
error_log is set to level: warn

Checking for dbus/python-dbus...
dbus daemon is running.
python-dbus version: 0.83.0

------------------------------------
| COMPILE AND RUNTIME DEPENDENCIES |
------------------------------------

note: To check for compile-time only dependencies, re-run hp-check with the -c parameter (ie, hp-check -c).
note: To check for run-time only dependencies, re-run hp-check with the -r parameter (ie, hp-check -r).

Checking for dependency: CUPS - Common Unix Printing System...
OK, found.

Checking for dependency: CUPS devel- Common Unix Printing System development files...
OK, found.

Checking for dependency: CUPS image - CUPS image development files...
OK, found.

Checking for dependency: DBus - Message bus system...
OK, found.

Checking for dependency: gcc - GNU Project C and C++ Compiler...
OK, found.

Checking for dependency: GhostScript - PostScript and PDF language interpreter and previewer...
OK, found.

Checking for dependency: libcrypto - OpenSSL cryptographic library...
OK, found.

Checking for dependency: libjpeg - JPEG library...
OK, found.

Checking for dependency: libnetsnmp-devel - SNMP networking library development files...
OK, found.

Checking for dependency: libpthread - POSIX threads library...
OK, found.

Checking for dependency: libtool - Library building support services...
OK, found.

Checking for dependency: libusb - USB library...
OK, found.

Checking for dependency: make - GNU make utility to maintain groups of programs...
OK, found.

Checking for dependency: PIL - Python Imaging Library (required for commandline scanning with hp-scan)...
OK, found.

Checking for dependency: PolicyKit - Administrative policy framework...
OK, found.

Checking for dependency: PyQt 4 DBus - DBus Support for PyQt4...
OK, found.

Checking for dependency: Python DBus - Python bindings for DBus...
OK, found.

Checking for dependency: Python devel - Python development files...
OK, found.

Checking for dependency: Python libnotify - Python bindings for the libnotify Desktop notifications...
OK, found.

Checking for dependency: Python XML libraries...
OK, found.

Checking for dependency: Python 2.3 or greater - Required for fax functionality...
OK, found.

Checking for dependency: Python 2.2 or greater - Python programming language...
OK, found.

Checking for dependency: Reportlab - PDF library for Python...
OK, found.

Checking for dependency: SANE - Scanning library...
OK, found.

Checking for dependency: SANE - Scanning library development files...
OK, found.

Checking for dependency: scanimage - Shell scanning program...
OK, found.

Checking for dependency: xsane - Graphical scanner frontend for SANE...
OK, found.

----------------------
| HPLIP INSTALLATION |
----------------------

Currently installed HPLIP version...
HPLIP 3.12.4 currently installed in '/usr/share/hplip'.

Current contents of '/etc/hp/hplip.conf' file:
# hplip.conf. Generated from hplip.conf.in by configure.

[hplip]
version=3.12.4

[dirs]
home=/usr/share/hplip
run=/var/run
ppd=/usr/share/ppd/HP
ppdbase=/usr/share/ppd
doc=/usr/share/doc/hplip-3.12.4
icon=/usr/share/applications
cupsbackend=/usr/lib/cups/backend
cupsfilter=/usr/lib/cups/filter
drv=/usr/share/cups/drv/hp

# Following values are determined at configure time and cannot be changed.
[configure]
network-build=yes
pp-build=no
gui-build=yes
scanner-build=yes
fax-build=yes
dbus-build=yes
cups11-build=no
doc-build=yes
shadow-build=no
hpijs-install=no
foomatic-drv-install=no
foomatic-ppd-install=no
foomatic-rip-hplip-install=no
hpcups-install=yes
cups-drv-install=yes
cups-ppd-install=no
internal-tag=3.12.4
restricted-build=no
ui-toolkit=qt4
qt3=no
qt4=yes
policy-kit=no
hpijs-only-build=no
lite-build=no
udev-acl-rules=yes
hpcups-only-build=no
hpijs-only-build=no

Current contents of '/var/lib/hp/hplip.state' file:
[plugin]
eula = 1
version = 3.12.4
installed = 1

Current contents of '~/.hplip/hplip.conf' file:
[last_used]
printer_name =
working_dir = .
device_uri = "hp:/usb/HP_LaserJet_Professional_P1102?serial=000000000Q82JLL1SI1c"

[commands]
scan = /usr/bin/xsane -V %SANE_URI%

[upgrade]
notify_upgrade = false
last_upgraded_time = 1335087735
latest_available_version = 3.12.4
pending_upgrade_time = 0

[installation]
version = 3.12.4
date_time = 22/04/2012 20:45:35

[settings]
systray_messages = 0
systray_visible = 0

[Scanner_plugins]
bb_soap.so = Present
bb_soapht.so = Present
bb_marvell.so = Present

[Printer_plugins]
lj.so = Present

[refresh]
rate = 30
enable = false
type = 1

[fax]
email_address =
voice_phone =

[polling]
enable = false
device_list =
interval = 5

[Fax_plugins]
fax_marvell.so = Present

--------------------------
| DISCOVERED USB DEVICES |
--------------------------

No devices found.

---------------------------------
| INSTALLED CUPS PRINTER QUEUES |
---------------------------------

HP_LaserJet_Professional_P1102
------------------------------
Type: Printer
Device URI: hp:/usb/HP_LaserJet_Professional_P1102?serial=000000000Q82JLL1SI1c
PPD: /etc/cups/ppd/HP_LaserJet_Professional_P1102.ppd
PPD Description: HP LaserJet Professional p1102, hpcups 3.12.4, requires proprietary plugin
Printer status: la stampante HP_LaserJet_Professional_P1102 è in attesa. Abilitata da d/usr/lib/cups/backend/hp failed
Required plug-in status: Installed
error: Unable to communicate with device (code=12): hp:/usb/HP_LaserJet_Professional_P1102?serial=000000000Q82JLL1SI1c
error: Device not found
error: Communication status: Failed

----------------------
| SANE CONFIGURATION |
----------------------

'hpaio' in '/etc/sane.d/dll.conf'...
OK, found. SANE backend 'hpaio' is properly set up.

Checking output of 'scanimage -L'...

No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).

---------------------
| PYTHON EXTENSIONS |
---------------------

Checking 'cupsext' CUPS extension...
OK, found.

Checking 'pcardext' Photocard extension...
OK, found.

Checking 'hpmudext' I/O extension...
OK, found.

Checking 'scanext' SANE scanning extension...
OK, found.

-----------------
| USB I/O SETUP |
-----------------

Checking for permissions of USB attached printers...

HP Device 0x2a at 002:006:
    Device URI: hp:/usb/HP_LaserJet_Professional_P1102?serial=000000000Q82JLL1SI1c
    Device node: /dev/bus/usb/002/006
    Mode: 0664

---------------
| USER GROUPS |
---------------

mario adm lp dialout cdrom plugdev lpadmin admin sambashare

-----------
| SUMMARY |
-----------

error: 1 error or warning.

I have a strong suspicion that hplip has a problem in dealing with the usb.
Advice will be greatly appreciated!
Thanks!