Got it to work by actually not using the dx9 mode (Mode=0 in ddraw.ini) and setting COLOUR_BITS=16 in f2_res.ini, now it runs like a charm even with fullscreen and both monitors on.
Running Win7 x64, I'm having similar problems as NFSlugger13.
If I try to run the game with directx9 enabled it gives me the same error. However, if I disable my second monitor (using an ATI card) it starts but the video still looks wonky (but with correct colors).
It starts in windowed...