Exception spam in server console

[Insane96]

I don't know when that happened sorry

[10:40:45] [Server thread/FATAL] [minecraft/MinecraftServer]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_111]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_111]
	at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:723) [MinecraftServer.class:?]
	at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:397) [nz.class:?]
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) [MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_111]
Caused by: java.lang.NullPointerException
	at vazkii.arl.util.AbstractDropIn.getCapability(AbstractDropIn.java:21) ~[AbstractDropIn.class:?]
	at net.minecraftforge.common.capabilities.CapabilityDispatcher.getCapability(CapabilityDispatcher.java:108) ~[CapabilityDispatcher.class:?]
	at net.minecraft.item.ItemStack.getCapability(ItemStack.java:1170) ~[aip.class:?]
	at vazkii.arl.util.DropInHandler.getDropInHandler(DropInHandler.java:109) ~[DropInHandler.class:?]
	at vazkii.arl.util.DropInHandler.executeDropIn(DropInHandler.java:92) ~[DropInHandler.class:?]
	at vazkii.arl.network.message.MessageDropIn.lambda$handleMessage$0(MessageDropIn.java:29) ~[MessageDropIn.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_111]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_111]
	at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
	... 5 more