This sounds like a lock-file issue. It is mentioned in the documentation.
You might have an old lock-file that was not deleted. (possibly when the system was not shut down correctly?)
My suggestion is to boot up and look for a lock-file before launching QjoyPad. If you find one, delete it and then try launching QjoyPad.
Note: Make sure you don't have any instance of QjoyPad running before deleting a lock-file (if you can find the lock file)
ps -e | grep qjoypad