Hopper: java.lang.NullPointerException

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-247587/

Crash:

java.lang.NullPointerException
	at acs.a(SourceFile:55)
	at vb.a(SourceFile:292)
	at wz.a(SourceFile:58)
	at vx.a(SourceFile:238)
	at kv.a(SourceFile:649)
	at fs.a(SourceFile:32)
	at eb.b(SourceFile:63)
	at kv.e(SourceFile:69)

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

---- Minecraft Crash Report ----
// I just don't know what went wrong :(

Time: 27-09-2013 15:03
Description: Ticking memory connection

java.lang.NullPointerException
	at acs.a(SourceFile:55)
	at vb.a(SourceFile:292)
	at wz.a(SourceFile:58)
	at vx.a(SourceFile:238)
	at kv.a(SourceFile:649)
	at fs.a(SourceFile:32)
	at eb.b(SourceFile:63)
	at kv.e(SourceFile:69)
	at ky.b(SourceFile:40)
	at box.b(SourceFile:83)
	at net.minecraft.server.MinecraftServer.u(SourceFile:494)
	at net.minecraft.server.MinecraftServer.t(SourceFile:411)
	at bou.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 acs.a(SourceFile:55)
	at vb.a(SourceFile:292)
	at wz.a(SourceFile:58)
	at vx.a(SourceFile:238)
	at kv.a(SourceFile:649)
	at fs.a(SourceFile:32)
	at eb.b(SourceFile:63)
	at kv.e(SourceFile:69)

-- Ticking connection --
Details:
	Connection: kv@1e3594d
Stacktrace:
	at ky.b(SourceFile:40)
	at box.b(SourceFile:83)
	at net.minecraft.server.MinecraftServer.u(SourceFile:494)
	at net.minecraft.server.MinecraftServer.t(SourceFile:411)
	at bou.t(SourceFile:121)
	at net.minecraft.server.MinecraftServer.run(SourceFile:346)
	at jc.run(SourceFile:582)

-- System Details --
Details:
	Minecraft Version: 13w39b
	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, sharing), Oracle Corporation
	Memory: 115964752 bytes (110 MB) / 372826112 bytes (355 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 883 (49448 bytes; 0 MB) allocated, 737 (41272 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 95 (5320 bytes; 0 MB) allocated, 89 (4984 bytes; 0 MB) used
	Player Count: 1 / 8; [kq['doggeada'/89, l='Castle war', x=1036,50, y=4,00, z=457,33]]
	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-247587/14599777/