I KNOW WHAT THIS ERROR IS!
ITS THE INFERNUS!!
if you killed playboy and got his mansion, you also will have his orange infernus..when i got his orange infernus i had replaced it as a lambo murcielago lp640 but recently i replaced it to a reventon and thats when i started getting this error, after that i tried reinstalling about 3 times (therefore reverting it back to the original infernus) with no luck. ive just reinstalled the lambo lp640 and it works fine!! no need to delete save game or anything, just go back to the car you had when you killed playboy as the infernus