Resurrecting this one. Had the same thing happen on the tuner screws for the JBA4M. Pre-drilled 1.5mm to correct depth. Wound screws in slowly but 3 have broken off. I examined the screws closely and they are certainly of inferior quality and not up to the task. Adam was commendably quick with an email reply but could offer nothing more than replacement with similar inferior screws or suggested go out and buy decent ones. I'll go the latter. Some good information above that I will be utilising today.
However, this is obviously a continuing problem that should be addressed by Pitbull and the factory, one would think.