Feed the beast server crash

java.lang.NullPointerException
	at codechicken.core.world.WorldExtensionManager.postTick(WorldExtensionManager.java:248)
	at codechicken.core.world.WorldExtensionManager.access$5(WorldExtensionManager.java:246)
	at codechicken.core.world.WorldExtensionManager$WorldExtensionServerTickHandler.tickEnd(WorldExtensionManager.java:166)
	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:847)
	at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:320)
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:732)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:614)
	at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:573)