Hopper: java.lang.NullPointerException 13w39a

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-242413/

Crash:

java.lang.NullPointerException
	at eb.b(SourceFile:116)
	at eb.a(SourceFile:40)

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

---- Minecraft Crash Report ----
// I blame Dinnerbone.

Time: 26/09/13 14:38
Description: Sending packet

java.lang.NullPointerException
	at eb.b(SourceFile:116)
	at eb.a(SourceFile:40)
	at kv.b(SourceFile:434)
	at ln.b(SourceFile:173)
	at jh.a(SourceFile:92)
	at bov.b(SourceFile:73)
	at net.minecraft.server.MinecraftServer.u(SourceFile:494)
	at net.minecraft.server.MinecraftServer.t(SourceFile:411)
	at bos.t(SourceFile:121)
	at net.minecraft.server.MinecraftServer.run(SourceFile:346)
	at jc.run(SourceFile:582)


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

-- Head --
Stacktrace:
	at eb.b(SourceFile:116)
	at eb.a(SourceFile:40)

-- Packet being sent --
Details:
	Packet ID: 200
	Packet class: fd
Stacktrace:
	at kv.b(SourceFile:434)
	at ln.b(SourceFile:173)
	at jh.a(SourceFile:92)
	at bov.b(SourceFile:73)
	at net.minecraft.server.MinecraftServer.u(SourceFile:494)
	at net.minecraft.server.MinecraftServer.t(SourceFile:411)
	at bos.t(SourceFile:121)
	at net.minecraft.server.MinecraftServer.run(SourceFile:346)
	at jc.run(SourceFile:582)

-- System Details --
Details:
	Minecraft Version: 13w39a
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_40, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 128067032 bytes (122 MB) / 211292160 bytes (201 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 733 (41048 bytes; 0 MB) allocated, 733 (41048 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 93 (5208 bytes; 0 MB) allocated, 93 (5208 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-242413/14409373/