RagePastry

Having a problem loading the mod onto my server, when i play single player with my server mod list nothing bad happens but when i try and play on the server i crash after loading and it gives me this. "System.Exception: Don't know how to instantiate item of class 'SmartSmeltableItem' did you forget to register a mapping?" I remove this mod and i can join the server again so i have it disabled for now.