What is the specific error it throws... or does it crash without an error.

You should load your modified exe in IDA Pro and step through the code after your modified Jump to see if it is infact doing CRC checks or not and just go in and jump past those as well.

If you debug it you can see where in the code its erroring and for what specific reason, and take appropriate action. At the very least it will give ppl you ask a better clue as to what is going wrong.