Grand Theft Auto 4 (GTA 4)
The Cheat Happens trainers I have run flawlessly on Vista x64. Try re-downloading and putting the trainers in the game executable directory.
either your computer is blocking the trainer, you have incorrect version of live, incorrect version of the game, or you have to make sure that the little wanted stars are visible before you activate the wanted option.
I run x64 win on my pc. works w/all the trainers so far(only i have to restart my pc each time before i play GTA4, cause i use up all the ram browsing etc )