And I go to so much trouble to make a nice, set-specific background for every carset!
However, I'm not sure it's the background that's your problem - that shouldn't cause the game to crash. From bitter experience, I'd check:
That you haven't altered the wheel jams from ones you know work in GP3-2000 - might seem odd, but they cause me some real headaches
That you've converting hardware jams to hardware jams or software to software and not confusing the two.
That you have the right jams in the right slots - the jam IDs for the cars are slot specific, as are the cockpit jams - that might well cause a crash
Try laucnhign GP3-2000 using GPxPatch in debug mode - that should give you a clue as to what's going on.