Everything works fine for me. I had a few problems getting the infinite life to work on the first level, but it worked fine after. Also, due to many years of being a seasoned fps player, I hit the reload button "R" by instinct, which causes the trainer to reset by accident.
You've got to tell me your secret.. I've loaded old save games of later levels, started new games, etc. I can't get the life/mana option to work at all no matter what I try.