Since this is a specific software version rather than a widely published book or movie, here is a story inspired by the typical dark, surreal fantasy world of such RPGs:
The 55 in the filename often indicates a split archive. Ensure you have all parts: -RPG-.--.ROBFEOY.Ver.2.0 55.part1 , part2 , etc. If you only have a single file named 55 , it may be corrupted. -RPG-.--.ROBFEOY.Ver.2.0 55
The core program identifier ( Ragnarok Online Battle Festival: End of Year / Era of Youth). Since this is a specific software version rather