at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_239_ItemRegistrySFire_registerItems_Register.invoke(.dynamic) at net.minecraftforge.fml.common ...

When I write this issue, I have not got any other persuasive evidences but a report generated by Spark. It says your Ice and Fire Mod used a large amount of CPU resources, and cause my server lag (low ...