Hmmm...

Well this project IS definitely BETA.
My 4870 (10.10) was cranking right along without error until this afternoon, now all WUs appear to complete normally but end with an error code -161.
Never have gotten my 460 GTX (266.58 Driver) to complete a WU, GPU processing never starts, WU keeps restarting with progress of 0%.
One of my old 9800 GT cards (266.58 Driver) appears to be working but who knows how long that will take to complete a WU and if it validates when completed.

Was hoping to get at least my 100K stone before moving on but as much as this project has been screwed up in the past 24hrs it doesn't look like I'll get there.