Got a DirectX 10 card? tough luck for DirectX 10.1!
Yup, sucks to be you, looks like Microsoft are adding in extra things to DirectX 10.1 that wont work on DX10 cards, but the good news is that it doesn't look like there's much to worry about:
Here's the thing. DX10 hardware - such as the GeForce 8800 or the Radeon 2900 - won't work with the new 10.1 features. The 0.1 revision requires completely new hardware for support, thus royally cheesing off many gamers who paid top whack for their new hardware over the last few months on the basis of future game compatibility.
I think I'll go get that 8600 anyway....

