– Affected screen –
Details:
Screen name: bkf
Stacktrace:
at net.minecraft.client.Minecraft.l(SourceFile:1078)
at net.minecraft.client.Minecraft.K(SourceFile:574)
at net.minecraft.client.Minecraft.run(SourceFile:526)
at java.lang.Thread.run(Unknown Source)

– System Details –
Details:
Minecraft Version: 1.5.2
Operating System: Windows Vista (x86) version 6.1
Java Version: 1.5.0_18, Sun Microsystems Inc.
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Sun Microsystems Inc.
Memory: 494014480 bytes (471 MB) / 532807680 bytes (508 MB) up to 1065484288 bytes (1016 MB)
JVM Flags: 2 total; -Xms512m -Xmx1024m
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
LWJGL: 2.4.2
OpenGL: AMD Radeon HD 7670M GL version 4.2.11411 Compatibility Profile Context, ATI Technologies Inc.
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Texture Pack: Default
Profiler Position: N/A (disabled)
Vec3 Pool Size: ~_ERROR~ NullPointerException: null

java.lang.RuntimeException: Failed to check session lock, aborting
at ajt.h(SourceFile:45)
at ajt.<init>(SourceFile:31)
at ajp.<init>(SourceFile:16)
at ajq.a(SourceFile:83)
at net.minecraft.client.Minecraft.a(SourceFile:1363)
at awo.a(SourceFile:204)
at awo.a(SourceFile:296)
at axr.n(SourceFile:153)
at axr.m(SourceFile:115)
at net.minecraft.client.Minecraft.l(SourceFile:1078)
at net.minecraft.client.Minecraft.K(SourceFile:574)
at net.minecraft.client.Minecraft.run(SourceFile:526)
at java.lang.Thread.run(Unknown Source)
— END ERROR REPORT 9dac769d ----------