Hi, I was having the same problem on a few modpacks and found the problem. The mod is
Modzoic. I tested this on a 183 mod modpack and a 315 mod modpack. Nether would launch got NullPointerException: Initializing gameNullPointerException: Initializing game at moze_intel.projecte.gameObjs.ObjHandler.registerPhiloStoneSmelting. Took out Modzoic and projecte works fine.