No problem, but yeah, Optifine is still being fully updated last I saw, hopefully not long now, he seems to update fast (might already be updated by now).
Do *NOT* hijack other topics. Very rude. Make your own. Just split you off and moved you to the proper board (which you were not in any way, what the heck?!).
If you are using ModLoader.addOverride at all then you are indeed doing it *VERY* wrong. Never use ModLoader.addOverride. Just use setTextureFile on the block/item calls.
You cannot expect a response in 7 minutes...
Either way, look at your own error: The requested image path /gui/Dark Messiahs Mods/NetherRium/NetherRiumSword.png is not found
It is translating poorly.
Items have some storage (a short I think?), a flag can be set that lets you treat it as damage or as storage data, it cannot be both as it would overlap in the MC design.