Gears of War Message Board  

I tried many times and the game crashes when the trainer is running but doesn't when the trainer is not used.

Do you have any antivirus on? If so disable before you run the trainer. Have a look at this too Link

I getting the same thing when it does a game save or the game loads the next map.

These crashes are due to LIVE; it has a anti cheat protection that scans the game executable and if it detects any modifications it crashes the game (DEP if I recall correctly)
So every game that utilizes LIVE will have similar problems and usually a lot more issues too...

It has to do with the engine, not with something called cheatprotection. It because when creating caves and such you are accesing and executing areas in memory which could be used by other things, could be windows or somehing else:

www.updatexp.com/data-execution-prevention.html

Data Execution Prevention (DEP) helps prevent damage from viruses and other security threats that attack your computer by running (sometimes called executing) malicious code from memory locations that only Windows and other programs should use. This type of threat causes damage by taking over one or more memory locations in use by a program.

Yes DEP is mainly a protection against malicious software and other potential threats but it is also utilized in LIVE enabled games, try turning DEP off for GoW for example, it gives you an error that it can't be turned off for that application.

For me it only crashes in the cut scenes, but theres a way to get over that. Right at the cut scene starts, quickly de activate the cheats you pressed and then after the cut scene, just put it back on again. Ive been enjoying this game alot now since there is no crashes

try enother trainer