Hopper: java.lang.RuntimeException: Failed to check session lock, aborting

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-83947/

Crash:

java.lang.RuntimeException: Failed to check session lock, aborting
	at anq.h(SourceFile:44)
	at anq.<init>(SourceFile:30)
	at anm.<init>(SourceFile:16)
	at ann.a(SourceFile:68)
	at awb.a(SourceFile:1463)
	at ayx.e(SourceFile:158)
	at ayy.a(SourceFile:210)
	at axo.a(SourceFile:186)
	at ayx.a(SourceFile:183)

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

---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 13-9-6 16:49
Description: Rendering screen

java.lang.RuntimeException: Failed to check session lock, aborting
	at anq.h(SourceFile:44)
	at anq.<init>(SourceFile:30)
	at anm.<init>(SourceFile:16)
	at ann.a(SourceFile:68)
	at awb.a(SourceFile:1463)
	at ayx.e(SourceFile:158)
	at ayy.a(SourceFile:210)
	at axo.a(SourceFile:186)
	at ayx.a(SourceFile:183)
	at bho.b(SourceFile:720)
	at awb.V(SourceFile:713)
	at awb.e(SourceFile:642)
	at net.minecraft.client.main.Main.main(SourceFile:103)


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

-- Head --
Stacktrace:
	at anq.h(SourceFile:44)
	at anq.<init>(SourceFile:30)
	at anm.<init>(SourceFile:16)
	at ann.a(SourceFile:68)
	at awb.a(SourceFile:1463)
	at ayx.e(SourceFile:158)
	at ayy.a(SourceFile:210)
	at axo.a(SourceFile:186)
	at ayx.a(SourceFile:183)

-- Screen render details --
Details:
	Screen name: bof
	Mouse location: Scaled: (153, 169). Absolute: (306, 141)
	Screen size: Scaled: (427, 240). Absolute: (854, 480). Scale factor of 2
Stacktrace:
	at bho.b(SourceFile:720)
	at awb.V(SourceFile:713)
	at awb.e(SourceFile:642)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 13w36b
	Operating System: Windows XP (x86) version 5.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 221362328 bytes (211 MB) / 308551680 bytes (294 MB) up to 648740864 bytes (618 MB)
	JVM Flags: 3 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -Xmx640m
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Launched Version: 13w36b
	LWJGL: 2.9.0
	OpenGL: ATI Radeon X300/X550/X1050 Series GL version 2.1.8545 Release, ATI Technologies Inc.
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: ~~ERROR~~ NullPointerException: null

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-83947/8329909/