Ya, sometimes an anti-virus could just give a false positive and try to heh, "repair" ... the file by itself. Just download a new one.
--------------------------------------------------------------------------- Grammar and punctuation is the difference between; "I helped my uncle, Jack, off a horse." ...and... i helped my uncle jack off a horse.
Switch off your AV software or add an exception pointing to the trainer's folder or the trainer itself.
--------------------------------------------------------------------------- "(Laugh) I never met my brother, until the day he killed me. (Sigh) We are a... complicated family. Wouldn't you agree?" - Paxton Fettel
The same thing happened to me once with the new trainer. I pressed the gain xp button several times then it wouldn't stop giving me experience and when I made it go to level 50 (the max) it still kept on going. I had to actually restart my computer because it wouldn't stop even if I quit the game and the trainer and started it up again. I think it has something to do with your anti-virus mucking around with the trainer as well. Also, try not to spam the buttons, wait at least half a second between toggles.