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-191555/

Crash:

java.lang.RuntimeException: Failed to check session lock, aborting
	at alq.h(SourceFile:44)
	at alq.<init>(SourceFile:30)
	at alm.<init>(SourceFile:16)
	at aln.a(SourceFile:83)
	at atv.a(SourceFile:1417)
	at awh.e(SourceFile:157)
	at awi.a(SourceFile:210)
	at awg.a(SourceFile:173)
	at awh.a(SourceFile:183)

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

---- Minecraft Crash Report ----
// Quite honestly, I wouldn't worry myself about that.

Time: 9/19/13 5:08 PM
Description: Rendering screen

java.lang.RuntimeException: Failed to check session lock, aborting
	at alq.h(SourceFile:44)
	at alq.<init>(SourceFile:30)
	at alm.<init>(SourceFile:16)
	at aln.a(SourceFile:83)
	at atv.a(SourceFile:1417)
	at awh.e(SourceFile:157)
	at awi.a(SourceFile:210)
	at awg.a(SourceFile:173)
	at awh.a(SourceFile:183)
	at bfe.b(SourceFile:718)
	at atv.S(SourceFile:686)
	at atv.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)


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

-- Head --
Stacktrace:
	at alq.h(SourceFile:44)
	at alq.<init>(SourceFile:30)
	at alm.<init>(SourceFile:16)
	at aln.a(SourceFile:83)
	at atv.a(SourceFile:1417)
	at awh.e(SourceFile:157)
	at awi.a(SourceFile:210)
	at awg.a(SourceFile:173)
	at awh.a(SourceFile:183)

-- Screen render details --
Details:
	Screen name: blt
	Mouse location: Scaled: (308, 170). Absolute: (618, 349)
	Screen size: Scaled: (683, 346). Absolute: (1366, 691). Scale factor of 2
Stacktrace:
	at bfe.b(SourceFile:718)
	at atv.S(SourceFile:686)
	at atv.d(SourceFile:619)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.4
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 734117720 bytes (700 MB) / 913137664 bytes (870 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	AABB Pool Size: 1929 (108024 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	Launched Version: 1.6.4
	LWJGL: 2.9.0
	OpenGL: AMD Radeon HD 7310 GL version 4.2.11774 Compatibility Profile Context, ATI Technologies Inc.
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Pack: faithful32pack.zip
	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-191555/12440824/