I take it you are using Linux.
Your software sources may be temporarily down. Or you make have a networking problem. Can you connect to other sites?
Oops! I made a big mistake. I'm in the wrong place. You're right, I am using Linux, specifically, Fedora 11. I upgraded to Fedora 11 from Fedora 10. Everything seems to be working except it doesn't do the automatic updates.
Again, sorry I put this into a Windows 7 forum.