I have Win Vista 32-bit. At first it didnt worked for me, too. But then after a while i found a solution 4 myself. First rightclick on the Trainer and config it where it opens with admin-rights automatically. Start the Trainer. Then try not to check every option in the Trainer, but those who you really whishes to use. For me it was: SP, HP, Ammo, Fastfire HMG + Fastfire other weapons.
While i was testing it i noticed that melee weapons, hmg, and smack rifle worked well. other wepons didnt work well, if they did at all. and some other weaps arent tested by me right now.
Seems like the Trainer is pretty well designed for hmg

pretty useful 4 arcade mode if you dont ressource hack ur win chances xD