It would seem you are not the only one having the problems..
http://forums.avg.com...ad&act=show&id=122883
From trawling some other forums some people are saying that a un-install and re-install does fix it, then others are saying it doesn't! I've also seen a few people saying that it doesn't work most the time, but then occasionally it does.
From everything I've seen it looks like a general AVG problem at the moment and there may not be anything you can do on your local computer to fix the problem, but give a reinstall a go, you've got nothing to loose.