Hello, I have the same problem like you. When I switch on Shader Model 4.0, I can see various kinds of colors. I have 4870x2 and the latest drivers. I wanted to make some screens, but Fraps or ATi Tools didn't capture image. So I grabbed my camera and took some photos:
You can see various kinds of colors. But, when I switch off Shader Model 4.0, everything goes OK, I don't see any colors.
One user told me, that problem is in PhysX and ATi graphics cards don't know how to work with it. So, we just hope in any kind of patch, who 'll repair this bug or wtf is it.