GalacticCraft Fuel Loader Problem

java.lang.AbstractMethodError: micdoodle8.mods.galacticraft.core.tile.GCCoreTileEntityFuelLoader.demandedEnergyUnits()D
	at ic2.core.energy.Grid.prepareCalculation(Grid.java:187)
	at ic2.core.energy.EnergyNetLocal.onTickEnd(EnergyNetLocal.java:288)
	at ic2.core.energy.EnergyNetGlobal.onTickEnd(EnergyNetGlobal.java:46)
	at ic2.core.IC2.tickEnd(IC2.java:1619)
	at cpw.mods.fml.common.SingleIntervalHandler.tickEnd(SingleIntervalHandler.java:34)
	at cpw.mods.fml.common.FMLCommonHandler.tickEnd(FMLCommonHandler.java:141)
	at cpw.mods.fml.common.FMLCommonHandler.onPostWorldTick(FMLCommonHandler.java:282)
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:675)
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:585)
	at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:129)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:482)
	at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:582)