"doesn't work" is almost useless feedback.
Does the option say activated?
What version of game are you?
can you post debug info from trainer?
Launch the trainer
Launch the game
At main menu hit "F1" to activate trainer
Hit "Num 4" to activate Campaign Disciplines (wait for "Activated"
Be sure to use some ammo before hitting "Num 5" to activate unlimited ammo/items. May fail the first time.
Be sure to use some fuel before hitting "Num 6" to activate unlimited fuel. Usually works on the first try.
... (here is the trick) ...
You must engage the enemy before the trainer will allow you to activate "Num 7" Invincible Army.
Engage enemy... Pause combat... Select one unit... Hit "Num 7", immediately select any black spot around the unit, you should hear "Activated". You may have try twice. I never had to try a third time.