This was answered before in a prior post.
Here
It's been a LONG time since I used this, but I do remember that it will allow you to run an illegal character on your computer. If you try to go to a multi-game that does not have the same options selected, it will not allow you to join. There WERE many games online that allowed cracked characters though, so you can try them out there. Again, if you do this, you will be able to play your single player game with your illegal character.