[18:40:37] [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_265]
        at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_265]
        at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
        at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:924) [MinecraftServer.class:?]
        at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:456) [nz.class:?]
        at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:861) [MinecraftServer.class:?]
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:733) [MinecraftServer.class:?]
        at java.lang.Thread.run(Thread.java:748) [?:1.8.0_265]
Caused by: java.lang.NullPointerException
        at net.minecraft.network.datasync.EntityDataManager.func_187225_a(EntityDataManager.java:151) ~[nb.class:?]
        at com.pixelmonmod.pixelmon.entities.npcs.EntityNPC.getAIMode(EntityNPC.java:929) ~[EntityNPC.class:8.1.2]
        at com.pixelmonmod.pixelmon.entities.npcs.NPCRelearner.func_70692_ba(NPCRelearner.java:227) ~[NPCRelearner.class:8.1.2]
        at net.minecraft.entity.EntityLiving.<init>(EntityLiving.java:102) ~[vq.class:?]
        at net.minecraft.entity.EntityCreature.<init>(EntityCreature.java:22) ~[vx.class:?]
        at com.pixelmonmod.pixelmon.entities.npcs.EntityNPC.<init>(EntityNPC.java:118) ~[EntityNPC.class:8.1.2]
        at com.pixelmonmod.pixelmon.entities.npcs.NPCRelearner.<init>(NPCRelearner.java:50) ~[NPCRelearner.class:8.1.2]
        at com.pixelmonmod.pixelmon.comm.packetHandlers.npc.CreateNPCPacket$Handler.onSyncMessage(CreateNPCPacket.java:138) ~[CreateNPCPacket$Handler.class:8.1.2]
        at com.pixelmonmod.pixelmon.comm.packetHandlers.npc.CreateNPCPacket$Handler.onSyncMessage(CreateNPCPacket.java:76) ~[CreateNPCPacket$Handler.class:8.1.2]
        at com.pixelmonmod.pixelmon.comm.packetHandlers.ISyncHandler.lambda$onMessage$0(ISyncHandler.java:17) ~[ISyncHandler.class:8.1.2]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_265]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_265]
        at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
        ... 5 more