Here's a question, did you upgrade to Lucid Lynx? Because couple of weeks ago, I
had the same thing that happen something like this, not like what you are
having. But about the same.

Also getdeb.net was down couple of weeks ago with a server issue.

You may want to wait to see if it goes away on it's own, or if you do have Lucid
Lynx, like what I said wait to see if it goes away on it's own, or reinstall it
see if it does the same thing.