MC and Forge version 1.8. could you tell me where i typed something in uppercase? because you sayd to type everything in lowercase.
EDIT: i tried using modelloader and thats my new line : ModelLoader.setCustomModelResourceLocation(enugget, 0, new ModelResourceLocation(MODID + ":emerald_nugget", "inventory"));
but i get the same error : [15:16:27] [Client thread/ERROR] [FML]: Model definition for location extendedemeralds:EmeraldNugget#inventory not found