This game has two distributed versions - retail (box) and Steam (digital download). If you do observe around here you should see some other game trainer were made specific for Steam version while this one has been made for retail version and not mentioned a Steam one.
Did you buy the game via Steam directly? Can you use this trainer with this game? I cannot use it no matter how I tried. You can hear "trainer activated" then you can press desired button and heard "on" but nothing happened. The game did not crash but trainer did not work. That's it.