Hopper: java.lang.NullPointerException 13w37b

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-144930/

Crash:

java.lang.NullPointerException
	at ea.b(SourceFile:116)
	at ea.a(SourceFile:41)

The following is the first clean report made public about this crash:

---- Minecraft Crash Report ----
// Why is it breaking :(

Time: 13/09/13 9:01 PM
Description: Sending packet

java.lang.NullPointerException
	at ea.b(SourceFile:116)
	at ea.a(SourceFile:41)
	at ku.b(SourceFile:432)
	at ln.b(SourceFile:170)
	at jg.a(SourceFile:86)
	at boc.b(SourceFile:73)
	at net.minecraft.server.MinecraftServer.u(SourceFile:483)
	at net.minecraft.server.MinecraftServer.t(SourceFile:400)
	at bnz.t(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:334)
	at jb.run(SourceFile:577)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at ea.b(SourceFile:116)
	at ea.a(SourceFile:41)

-- Packet being sent --
Details:
	Packet ID: 200
	Packet class: fc
Stacktrace:
	at ku.b(SourceFile:432)
	at ln.b(SourceFile:170)
	at jg.a(SourceFile:86)
	at boc.b(SourceFile:73)
	at net.minecraft.server.MinecraftServer.u(SourceFile:483)
	at net.minecraft.server.MinecraftServer.t(SourceFile:400)
	at bnz.t(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:334)
	at jb.run(SourceFile:577)

-- System Details --
Details:
	Minecraft Version: 13w37b
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 111366024 bytes (106 MB) / 188272640 bytes (179 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 2 (112 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Player Count: 0 / 8; []
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-144930/10412940/