trainer has been working with proper version since inception.

I blew yet another 10 minutes today testing it yet again and it works fine.

run game
enter game where you can drive around
run trainer
F1 to activate trainer
go back into game
press numpad 4
press ESC to enter menu and see credits
says ACTIVATED then says DEACTIVATED
press numpad 5
says ACTIVATED
press ESC to re-enter where you can drive
press ESC to re-enter menu
credits changed

repeatble, and works 100% here.

I have no other suggestions for you.