java.lang.NullPointerException: at net.minecraft.client.multiplayer.NetClientHandler . func_72456_a ( NetClientHandler.java: 787 ) at net.minecraft.network.packet.Packet53BlockChange . func_73279_a ( SourceFile: 44 ) at net.minecraft.network.MemoryConnection . func_74428_b ( MemoryConnection.java: 89 ) at net.minecraft.client.multiplayer.NetClientHandler . func_72551_d ( NetClientHandler.java: 281 ) at net.minecraft.client.multiplayer.WorldClient . func_72835_b ( WorldClient.java: 99 ) at net.minecraft.client.Minecraft . func_71407_l ( Minecraft.java: 1930 ) at net.minecraft.client.Minecraft . func_71411_J ( Minecraft.java: 910 ) at net.minecraft.client.Minecraft . func_99999_d ( Minecraft.java: 838 ) at net.minecraft.client.main.Main . main ( SourceFile: 101 ) at sun.reflect.NativeMethodAccessorImpl . invoke0 ( NativeMethodAccessorImpl.java: -2 ) at sun.reflect.NativeMethodAccessorImpl . invoke ( NativeMethodAccessorImpl.java: 57 ) at sun.reflect.DelegatingMethodAccessorImpl . invoke ( DelegatingMethodAccessorImpl.java: 43 ) at java.lang.reflect.Method . invoke ( Method.java: 606 ) at net.minecraft.launchwrapper.Launch . launch ( Launch.java: 131 ) at net.minecraft.launchwrapper.Launch . main ( Launch.java: 27 )