Yes, I work with Threadfire, as well. But now my machine is ok again. Avast just updated with VPS 110318-0 automatically. And I checked the manual option - works now well, too.
I guess there was a temporay problem with the update-server. I am happy now.
But I do not know whether arjun_vas2005 is happy, as well. Actually, he adressed the problem first.
Best wishes
Mc User