You can be connected to live while using the trainer, the trainer just isn't compatible with the version of the game you have. It seems different countries have different version numbers.
@oyyzj, if you have the retail disc version or the steam version and the version number of your game is the same as listed in the trainer description then it will work.
[Edited by McDurbin, 5/20/2012 6:00:05 PM]
xlive is bypassed with our trainer.
crashing using trainer is likely due to the version of the game by user not matching
best,
Cal