java.lang.NullPointerException
at Reflector.callInt(Reflector.java:214)
at jw.d(EntityLiving.java:1030)
at jw.a(EntityLiving.java:882)
at nu.a(SourceFile:43)
at jn.e(Entity.java:996)
at jn.d(Entity.java:856)
at jw.e(EntityLiving.java:1369)
at jw.d(EntityLiving.java:1601)
at nu.d(SourceFile:25)
at oa.d(SourceFile:61)
at jw.h_(EntityLiving.java:688)
at nu.h_(SourceFile:30)
at up.a(World.java:2022)
at gr.a(WorldServer.java:538)
at up.g(World.java:1986)
at up.h(World.java:1867)
at gr.h(WorldServer.java:437)
at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:616)
at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:547)
at axv.p(IntegratedServer.java:102)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:453)
at ep.run(SourceFile:539)
at Reflector.callInt(Reflector.java:214)
at jw.d(EntityLiving.java:1030)
at jw.a(EntityLiving.java:882)
at nu.a(SourceFile:43)
at jn.e(Entity.java:996)
at jn.d(Entity.java:856)
at jw.e(EntityLiving.java:1369)
at jw.d(EntityLiving.java:1601)
at nu.d(SourceFile:25)
at oa.d(SourceFile:61)
at jw.h_(EntityLiving.java:688)
at nu.h_(SourceFile:30)
at up.a(World.java:2022)
at gr.a(WorldServer.java:538)
at up.g(World.java:1986)
at up.h(World.java:1867)
at gr.h(WorldServer.java:437)
at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:616)
at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:547)
at axv.p(IntegratedServer.java:102)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:453)
at ep.run(SourceFile:539)
http://www.minecraftforum.net/topic/1383256-advanced-minecraft-error-test/