Unfortunately, @genio2k is right, I've tried all the DLC I could get my hands on from various sites and nothing works. It needs to go to PSN temporarily to make sure you have a 'licence' or something for the DLC to activate. Until there is a version released with all the DLC included we're stuck with the base game it seems
DUPLEX has just cracked the necessity to have mandatory PSN access for games....maybe they will RELEASE a new version of FINAL FANTASY 15 that works with ALL DLC's!