---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!

Time: 28/04/13 14:01
Description: Exception in server tick loop

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 ajq.a(SourceFile:158)
	at net.minecraft.server.MinecraftServer.b(SourceFile:112)
	at net.minecraft.server.MinecraftServer.a(SourceFile:146)
	at hz.c(SourceFile:176)
	at net.minecraft.server.MinecraftServer.run(SourceFile:306)
	at gp.run(SourceFile:573)


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

-- System Details --
Details:
	Minecraft Version: 1.5.1
	Operating System: Linux (amd64) version 3.2.13-grsec-xxxx-grs-ipv6-64
	Java Version: 1.7.0, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 1042650048 bytes (994 MB) / 1065025536 bytes (1015 MB) up to 2138767360 bytes (2039 MB)
	JVM Flags: 6 total; -Xmx2048M -Xms1024M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalPacing -XX:ParallelGCThreads=1 -XX:+AggressiveOpts
	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
	Profiler Position: N/A (disabled)
	Player Count: 0 / 20; []
	Is Modded: Unknown (can't tell)
	Type: Dedicated Server (map_server.txt)