I would suggest you follow the user manual http://www.skyrc.com/index.php?route=product/product/download&download_id=5 to reset it to factory default and ensure you have adequate (i.e. Full) battery power when doing the setup (and connected to the motor, just remove propellers for safety if you have any attached)
Also in your code the closing } for if something is available on Serial should be after all the handling code afterwards otherwise you call that at every loop messing around with timing (you only set the invomungByte to '*' if the code had been matched, but the serial read will also hold CR or LF which you don't clear.