Hopper: java.lang.NullPointerException 13w38c

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-197251/

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 ----
// You should try our sister game, Minceraft!

Time: 20-9-13 18:02
Description: Sending packet

java.lang.NullPointerException
	at eb.b(SourceFile:116)
	at eb.a(SourceFile:40)
	at kv.b(SourceFile:430)
	at lo.b(SourceFile:170)
	at jh.a(SourceFile:86)
	at bow.b(SourceFile:72)
	at net.minecraft.server.MinecraftServer.u(SourceFile:487)
	at net.minecraft.server.MinecraftServer.t(SourceFile:404)
	at bot.t(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:338)
	at jc.run(SourceFile:581)


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:430)
	at lo.b(SourceFile:170)
	at jh.a(SourceFile:86)
	at bow.b(SourceFile:72)
	at net.minecraft.server.MinecraftServer.u(SourceFile:487)
	at net.minecraft.server.MinecraftServer.t(SourceFile:404)
	at bot.t(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:338)
	at jc.run(SourceFile:581)

-- System Details --
Details:
	Minecraft Version: 13w38c
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.6.0_31, Sun Microsystems Inc.
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Sun Microsystems Inc.
	Memory: 131379960 bytes (125 MB) / 375476224 bytes (358 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 10164 (569184 bytes; 0 MB) allocated, 10164 (569184 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 16811 (941416 bytes; 0 MB) allocated, 16811 (941416 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-197251/12629166/