Those two threads, the second is a continuation of the first actually, are about this problem and it was started September 27, 2009 and the last post was 12 hours ago. It's still an ongoing problem and supposedly Microsoft has been investigating it, for like 2 years almost. You can have a read through to see if any solutions work for you but as far as I can tell none of the possible solutions worked permenantly for anybody. The problem always came back eventually. So, apparently we're still waiting on an actual fix from Microsoft.
The very first post in the second thread is stated as the most successful resolution found so far so try it out. Essentially it's searching for any occurrence of 'DontRefresh' in the registry and changing the value from 1 to 0. Maybe it'll work for you. Good Luck.