update-manager crashes at start-up

[Manuel Spuhler]

First, I'm using Ubuntu 12.04
and I'm not able to get the version of the package, if I try:

mspuhler@mspuhler-laptop:~$ sudo apt-cache policy update-manager
E: Encountered a section with no Package: header
E: Problem with MergeList /var/lib/apt/lists/extras.ubuntu.com_ubuntu_dists_precise_main_binary-amd64_Packages
E: Die Paketliste oder die Statusdatei konnte nicht eingelesen oder geöffnet werden.

The Update-Tool crashes and says:

"E:Encountered a section with no Package: header, E:Problem with MergeList /var/lib/apt/lists/extras.ubuntu.com_ubuntu_dists_precise_main_binary-amd64_Packages, E:Die Paketliste oder die Statusdatei konnte nicht eingelesen oder geöffnet werden."

I know the last part is in german, but because of this bug I cannot change the language of my Ubuntu. Also I cannot report a bug automatically, because it says that the package-name was incorrect.

Checked the box "security vulnerability", because I cannot update my computer, so I have not the ability to be protected with the newest updates. If it's wrong please change it.
Thanks

[Tyler Hicks (tyhicks)]

Thanks for taking the time to report this bug and helping to make Ubuntu better. We appreciate the difficulties you are facing, but this appears to be a "regular" (non-security) bug. I have unmarked it as a security issue since this bug does not show evidence of allowing attackers to cross privilege boundaries nor directly cause loss of data/privacy. Please feel free to report any other bugs you may find.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Owain Shave (owainshave83-s)]

I have encountered the same bug. I don't know if it's relevant, but my only internet access is on the work network, where a filter is used to restrict our access to download sites. As far as I can tell, this doesn't filter the normal ubuntu repositories.

[Owain Shave (owainshave83-s)]

I also get the same message when trying to install software.