The first link notes someone that deleted the files in a specific subdirectory. Have you done this and did you try the other things people have noted to cure this?
I am fairly new to Linux but am finding it very enjoyable. Currently I am running the newest release of Ubuntu and it works great. I dual boot with Windows 2000 Pro on a large Sata drive.
I needed a proprietary program and was unable to find it in repositories so I installed the CNR client from cnr.com. I was able to use this app quit well, at first. But now icon is black instead of green and anything I try to install using it comes up with error " unable to write to data base". I tried to uninstall through add/remove, no CNR remove link. Need help to uninstall. Reinstall failed also. Can not find help for this problem on their site or forums either.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic