To answer an earlier question - The trainer options will all work in other modes, like spec-ops. It won't work for multiplayer, because that's a different launch of the game (different .exe which the trainer won't target). However! If you switch to MP, I wouldn't leave any trainers running in the background as it could still be picked up by any anti-cheats which may be running (I don't know if/what the game uses).
If it's the bit where you're following the tanks through the streets then instead of moving forward go through the door ( or a window , can't remember which )to the right and continue in the building until your officer ( who you're following ) joins you and then keep following him as normal That seemed to get me past the overflow bug ( That one anyway , don't know if there's another one ? ) .