Please calm down. I'm not that sure yet. Does this only happen when you visit facebook? If that's the case, there could be a program that monitors your surfing activities and if you go to a site that the person that deployed the program does not want you, it makes your session end.
This is just my sense, I'll try if I can to help you know how to find the software and remove it. I'm not that of an expert though.
If this is true I believe it's best if this thread is moved to Linux Security.
Last edited by konsolebox; 08-18-2010 at 07:59 AM.