Did you follow the directions here:
https://wpilib.screenstepslive.com/s...anual-id=24192
I had done that before and it didn't seem to work, but I tried it again, and was able to finally get it to work. Pay particular attention to the need for the double backslashes in the path. Also, if 'java' is not in your path, you need to provide the full path for it.