It should work just fine, make sure that the volume is correct (its happened to me where i hear the game just fine but for some reason the trainer is muted) also make sure you download the retail trainer and not the steam one, its not the same thing. (or at least to my knowledge its not the same thing.) Run as admin trainer first of course. Then game, on menu screen press F1, and you should hear it. Also even if you dont hear it, alt-tab and check if at the bottom of the trainer it says, game found! trainer activated.
[Edited by crsojo, 11/1/2010 11:15:32 AM]