error

Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_45]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_45]
	at net.minecraft.util.Util.runTask(Util.java:26) [Util.class:?]
	at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1108) [Minecraft.class:?]
	at net.minecraft.client.Minecraft.run(Minecraft.java:406) [Minecraft.class:?]
	at net.minecraft.client.main.Main.main(Main.java:118) [Main.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_45]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_45]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_45]
	at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_45]
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_45]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_45]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_45]
	at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_45]
	at net.minecraftforge.gradle.GradleStartCommon.launch(GradleStartCommon.java:97) [start/:?]
	at GradleStart.main(GradleStart.java:26) [start/:?]
Caused by: java.lang.NullPointerException
	at com.epiicthundercat.raft.rafttileentitity.TileEntitySeparator.readFromNBT(TileEntitySeparator.java:47) ~[TileEntitySeparator.class:?]
	at net.minecraft.tileentity.TileEntity.handleUpdateTag(TileEntity.java:374) ~[TileEntity.class:?]
	at net.minecraft.client.network.NetHandlerPlayClient.handleChunkData(NetHandlerPlayClient.java:803) ~[NetHandlerPlayClient.class:?]
	at net.minecraft.network.play.server.SPacketChunkData.processPacket(SPacketChunkData.java:110) ~[SPacketChunkData.class:?]
	at net.minecraft.network.play.server.SPacketChunkData.processPacket(SPacketChunkData.java:20) ~[SPacketChunkData.class:?]
	at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:15) ~[PacketThreadUtil$1.class:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_45]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_45]
	at net.minecraft.util.Util.runTask(Util.java:25) ~[Util.class:?]
	... 15 more