nProtect GameGuard (sometimes called GG) is an anti-cheating application developed by INCA Internet. It is bundled with many Asian multiplayer online games such as Phantasy Star Universe, GunZ: The Duel and Ragnarok Online to block malicious applications and common methods of cheating.
ERL files are log files that GameGuard creates while in operation.
You can receive further advises on problems concerning GameGuard that were not been able to be solved through methods in FAQ by sending these to the company.
The five ERL files ( npgl.erl, npgg.erl, npgmup.erl, npsc.erl, npgm.erl) which are located inside the GameGuard folder of the game folder are recreated every time the game is run.