There's a thread discussing some UI problems over on the WoW forums. Might be similar to what Bluepea and Kulgarr were seeing! Check out the thread, it's only a couple pages, but particularly try this:
Step 1 - Enter in chat:
/run SetCVar("raidFramesDisplayIncomingHeals",1)
Step 2 - Enter in chat:
/console reloadui
Hope that helps!
I came across the 1st suggestion you made in the forums plus I updated the drivers. Between those 2 it seemed to fix the problem! Yay!
Kull