Need for Speed Rivals doesn't launch

Hi all, I am trying to play my new game on a 2009 Imac running paralles and windows 7.

I am getting the following error when firts opeing the game:

DirectX function "CreatePixelShader for (null)" failed with E_INVALIDARG ("An invalid parameter was passed to the returning function.") GPU: "Parallels Display Adapter (WDDM)", Driver: Unknown

I have DirectX 10 3D acceleration enabled and 1024mb of video memory set.

Can anyone offer any help??

Cheers Taylor