Error executing task Ender Tanks

Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122)
	at java.util.concurrent.FutureTask.get(FutureTask.java:192)
	at net.minecraft.util.Util.func_181617_a(Util.java:48)
	at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:273)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
	at shetiphian.endertanks.common.misc.LocationManager.preformBlockUpdate(LocationManager.java:55)
	at shetiphian.endertanks.common.misc.LocationManager.lambda$doBlockUpdate$0(LocationManager.java:47)
	at shetiphian.endertanks.common.misc.LocationManager$$Lambda$11168/1036053032.run(Unknown Source)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at net.minecraft.util.Util.func_181617_a(Util.java:47)
	... 3 more