Some of you might have run into a false positive from AVG today when you went to launch WoW. Have a read of this link for all the details and how to fix it. Here is the official Blizzard response.
Datth
Blizzard Poster 0. Fmod.dll download link | 07/11/2007 08:12:18 PM UTC
UPDATE - 4:35 PM
AVG has fixed this with an updated definition. Please update it now!