Can't reload Synaptic Package Manager

Can you start "gnome-terminal" and could you post the output of "sudo apt-get update && sudo apt-get dist-upgrade -d" here?

And can have a look at https://answers.edge.launchpad.net/ubuntu/+source/installation-locale/+question/135907 as it appears to be the same as your problem.

house@house:~$ sudo apt-get update && sudo apt-get dist-upgrade -d
[sudo] password for house:
Get:1 http://dl.google.com stable Release.gpg [197B]
Get:2 http://extras.ubuntu.com maverick Release.gpg [316B]
Ign http://extras.ubuntu.com/ubuntu/ maverick/main Translation-en
Ign http://dl.google.com/linux/chrome/deb/ stable/main Translation-en
Hit http://archive.canonical.com maverick Release.gpg
Ign http://archive.canonical.com/ubuntu/ maverick/partner Translation-en
Hit http://us.archive.ubuntu.com maverick Release.gpg
Ign http://us.archive.ubuntu.com/ubuntu/ maverick/main Translation-en
Ign http://us.archive.ubuntu.com/ubuntu/ maverick/main Translation-en_US
Ign http://extras.ubuntu.com/ubuntu/ maverick/main Translation-en_US
Ign http://archive.canonical.com/ubuntu/ maverick/partner Translation-en_US
Hit http://archive.canonical.com maverick Release
Ign http://us.archive.ubuntu.com/ubuntu/ maverick/multiverse Translation-en
Ign http://us.archive.ubuntu.com/ubuntu/ maverick/multiverse Translation-en_US
Ign http://us.archive.ubuntu.com/ubuntu/ maverick/restricted Translation-en
Get:3 http://extras.ubuntu.com maverick Release [57.3kB]
Ign http://dl.google.com/linux/chrome/deb/ stable/main Translation-en_US
Get:4 http://dl.google.com stable Release [1,347B]
Ign http://us.archive.ubuntu.com/ubuntu/ maverick/restricted Translation-en_US
Ign http://us.archive.ubuntu.com/ubuntu/ maverick/universe Translation-en
Ign http://us.archive.ubuntu.com/ubuntu/ maverick/universe Translation-en_US
Hit http://us.archive.ubuntu.com maverick-updates Release.gpg
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-updates/main Translation-en
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-updates/main Translation-en_US
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-updates/multiverse Translation-en
Err http://extras.ubuntu.com maverick Release

Ign http://us.archive.ubuntu.com/ubuntu/ maverick-updates/multiverse Translation-en_US
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-updates/restricted Translation-en
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-updates/restricted Translation-en_US
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-updates/universe Translation-en
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-updates/universe Translation-en_US
Hit http://us.archive.ubuntu.com maverick-security Release.gpg
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-security/main Translation-en
Hit http://archive.canonical.com maverick/partner i386 Packages
Get:5 http://dl.google.com stable/main i386 Packages [1,094B]
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-security/main Translation-en_US
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-security/multiverse Translation-en
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-security/multiverse Translation-en_US
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-security/restricted Translation-en
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-security/restricted Translation-en_US
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-security/universe Translation-en
Ign http://us.archive.ubuntu.com/ubuntu/ maverick-security/universe Translation-en_US
Hit http://us.archive.ubuntu.com maverick Release
Hit http://us.archive.ubuntu.com maverick-updates Release
Hit http://us.archive.ubuntu.com maverick-security Release
Hit http://us.archive.ubuntu.com maverick/main Sources
Hit http://us.archive.ubuntu.com maverick/restricted Sources
Hit http://us.archive.ubuntu.com maverick/universe Sources
Hit http://us.archive.ubuntu.com maverick/multiverse Sources
Hit http://us.archive.ubuntu.com maverick/main i386 Packages
Hit http://us.archive.ubuntu.com maverick/restricted i386 Packages
Hit http://us.archive.ubuntu.com maverick/universe i386 Packages
Hit http://us.archive.ubuntu.com maverick/multiverse i386 Packages
Hit http://us.archive.ubuntu.com maverick-updates/main Sources
Hit http://us.archive.ubuntu.com maverick-updates/restricted Sources
Hit http://us.archive.ubuntu.com maverick-updates/universe Sources
Hit http://us.archive.ubuntu.com maverick-updates/multiverse Sources
Hit http://us.archive.ubuntu.com maverick-updates/main i386 Packages
Hit http://us.archive.ubuntu.com maverick-updates/restricted i386 Packages
Hit http://us.archive.ubuntu.com maverick-updates/universe i386 Packages
Hit http://us.archive.ubuntu.com maverick-updates/multiverse i386 Packages
Hit http://us.archive.ubuntu.com maverick-security/main Sources
Hit http://us.archive.ubuntu.com maverick-security/restricted Sources
Hit http://us.archive.ubuntu.com maverick-security/universe Sources
Hit http://us.archive.ubuntu.com maverick-security/multiverse Sources
Hit http://us.archive.ubuntu.com maverick-security/main i386 Packages
Hit http://us.archive.ubuntu.com maverick-security/restricted i386 Packages
Hit http://us.archive.ubuntu.com maverick-security/universe i386 Packages
Hit http://us.archive.ubuntu.com maverick-security/multiverse i386 Packages
Fetched 2,955B in 1s (2,378B/s)
Reading package lists... Done
W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://extras.ubuntu.com maverick Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY DB141E2302FDF932

W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/maverick/Release

W: Some index files failed to download, they have been ignored, or old ones used instead.
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  libutouch-grail1 libvlc5 libvlccore4 vlc vlc-data vlc-nox vlc-plugin-notify
  vlc-plugin-pulse
8 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 13.5MB of archives.
After this operation, 12.3kB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://us.archive.ubuntu.com/ubuntu/ maverick-updates/main libutouch-grail1 i386 1.0.16-0ubuntu1 [16.7kB]
Get:2 http://us.archive.ubuntu.com/ubuntu/ maverick-updates/universe libvlccore4 i386 1.1.4-1ubuntu1.1 [446kB]
Get:3 http://us.archive.ubuntu.com/ubuntu/ maverick-updates/universe vlc-data all 1.1.4-1ubuntu1.1 [7,781kB]
Get:4 http://us.archive.ubuntu.com/ubuntu/ maverick-updates/universe libvlc5 i386 1.1.4-1ubuntu1.1 [43.7kB]
Get:5 http://us.archive.ubuntu.com/ubuntu/ maverick-updates/universe vlc-plugin-pulse i386 1.1.4-1ubuntu1.1 [7,174B]
Get:6 http://us.archive.ubuntu.com/ubuntu/ maverick-updates/universe vlc-plugin-notify i386 1.1.4-1ubuntu1.1 [6,216B]
Get:7 http://us.archive.ubuntu.com/ubuntu/ maverick-updates/universe vlc i386 1.1.4-1ubuntu1.1 [2,049kB]
Get:8 http://us.archive.ubuntu.com/ubuntu/ maverick-updates/universe vlc-nox i386 1.1.4-1ubuntu1.1 [3,182kB]
Fetched 13.5MB in 1min 4s (209kB/s)
Download complete and in download only mode
house@house:~$

i can upgrade through the upgrade manager but i can't reload the list in synaptic package manager. i just tried again and i still get the error message.

that worked! thanks for your help!

Thanks actionparsnip, that solved my question.