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-144882/

Crash:

java.lang.RuntimeException: Failed to check session lock, aborting
	at aoc.h(SourceFile:44)
	at aoc.<init>(SourceFile:30)
	at any.<init>(SourceFile:16)
	at anz.a(SourceFile:68)
	at awo.a(SourceFile:1471)
	at ayk.a(SourceFile:202)
	at azi.a(SourceFile:169)
	at ayk.a(SourceFile:301)
	at azi.d(SourceFile:237)
	at azi.m(SourceFile:208)

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

---- Minecraft Crash Report ----
// This is a token for 1 free hug. Redeem at your nearest Mojangsta: [~~HUG~~]

Time: 16:10 13/09/13
Description: Updating screen events

java.lang.RuntimeException: Failed to check session lock, aborting
	at aoc.h(SourceFile:44)
	at aoc.<init>(SourceFile:30)
	at any.<init>(SourceFile:16)
	at anz.a(SourceFile:68)
	at awo.a(SourceFile:1471)
	at ayk.a(SourceFile:202)
	at azi.a(SourceFile:169)
	at ayk.a(SourceFile:301)
	at azi.d(SourceFile:237)
	at azi.m(SourceFile:208)
	at awo.m(SourceFile:1210)
	at awo.V(SourceFile:690)
	at awo.e(SourceFile:646)
	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 aoc.h(SourceFile:44)
	at aoc.<init>(SourceFile:30)
	at any.<init>(SourceFile:16)
	at anz.a(SourceFile:68)
	at awo.a(SourceFile:1471)
	at ayk.a(SourceFile:202)
	at azi.a(SourceFile:169)
	at ayk.a(SourceFile:301)
	at azi.d(SourceFile:237)
	at azi.m(SourceFile:208)

-- Affected screen --
Details:
	Screen name: bor
Stacktrace:
	at awo.m(SourceFile:1210)
	at awo.V(SourceFile:690)
	at awo.e(SourceFile:646)
	at net.minecraft.client.main.Main.main(SourceFile:103)

-- System Details --
Details:
	Minecraft Version: 13w37b
	Operating System: Windows XP (x86) version 5.1
	Java Version: 1.6.0_20, Sun Microsystems Inc.
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Sun Microsystems Inc.
	Memory: 368557616 bytes (351 MB) / 465956864 bytes (444 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 17538 (982128 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Launched Version: 13w37b
	LWJGL: 2.9.0
	OpenGL: Intel Eaglelake GL version 2.0.0 - Build 6.14.10.5047, Intel
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: עברית (IL)
	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-144882/10447187/