http://forums.worldofwarcraft.com/threa ... 1&pageNo=1A lot of them only work with desktop radeons, it seems to be the mobility radeons (for laptops) that are giving the most trouble, but there's some fixes for both in here. Seems to stem from ATI not releasing a new ATI driver in years for their radeons, and just reusing the old ones from older cards, combined with the new combat log.
Fast summary of the pages I read of things people said had worked:
Deleting and forcing WoW to recreate your WTF folder (not from prefetch)
Getting best (not necessarily newest) catalyst drivers
Changing the combat log settings