Server Crash Bukkit

2013-02-27 17:02:28 [INFO] §9Rutgerrrr dacht dat 'ie kon vliegen
2013-02-27 17:02:28 [INFO] [37;1m([37;22mUser[37;1m)([37;1mVincentovich[37;1m): Kopen[m
2013-02-27 17:02:31 [INFO] [37;1m([37;22mUser[37;1m)([37;1mlieese[37;1m): Onthoud dat geen geintjes hier[m
2013-02-27 17:02:33 [INFO] Rutgerrrr issued server command: /back
2013-02-27 17:02:33 [INFO] [ServerSigns] execute Command: tppos Aviatorgameguy 1518 42 -856
2013-02-27 17:02:33 [INFO] [33;22mTeleporting...[m
2013-02-27 17:02:33 [INFO] [37;1m([37;22mUser[37;1m)([37;1mTubbietoost[37;1m): voor wat?[m
2013-02-27 17:02:33 [INFO] [37;1m([37;22mUser[37;1m)([37;1mlieese[37;1m): oke wtf[m
2013-02-27 17:02:34 [INFO] [37;1m([37;22mUser[37;1m)([37;1mDOHmania[37;1m): hier kan deur[m
2013-02-27 17:02:35 [INFO] nielsguus issued server command: /
2013-02-27 17:02:37 [INFO] SantaClausIIIII [/94.212.161.35:49944] lost connection
2013-02-27 17:02:37 [INFO] [37;1m([37;22mUser[37;1m)([37;1mDOHmania[37;1m): nice[m
2013-02-27 17:02:39 [SEVERE] net.minecraft.server.v1_4_R1.ReportedException: Ticking entity
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:584)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:224)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)
2013-02-27 17:02:39 [SEVERE] Caused by: java.util.ConcurrentModificationException
2013-02-27 17:02:39 [SEVERE] 	at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:819)
2013-02-27 17:02:39 [SEVERE] 	at java.util.ArrayList$Itr.next(ArrayList.java:791)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.WorldServer.getTileEntities(WorldServer.java:584)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.EntityPlayer.j_(EntityPlayer.java:167)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.World.entityJoinedWorld(World.java:1332)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.WorldServer.entityJoinedWorld(WorldServer.java:548)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.World.playerJoinedWorld(World.java:1313)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.World.tickEntities(World.java:1191)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.WorldServer.tickEntities(WorldServer.java:445)
2013-02-27 17:02:39 [SEVERE] 	at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:580)
2013-02-27 17:02:39 [SEVERE] 	... 4 more
2013-02-27 17:02:39 [SEVERE] Encountered an unexpected exception ReportedException
net.minecraft.server.v1_4_R1.ReportedException: Ticking entity
	at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:584)
	at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:224)
	at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
	at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
	at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)
Caused by: java.util.ConcurrentModificationException
	at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:819)
	at java.util.ArrayList$Itr.next(ArrayList.java:791)
	at net.minecraft.server.v1_4_R1.WorldServer.getTileEntities(WorldServer.java:584)
	at net.minecraft.server.v1_4_R1.EntityPlayer.j_(EntityPlayer.java:167)
	at net.minecraft.server.v1_4_R1.World.entityJoinedWorld(World.java:1332)
	at net.minecraft.server.v1_4_R1.WorldServer.entityJoinedWorld(WorldServer.java:548)
	at net.minecraft.server.v1_4_R1.World.playerJoinedWorld(World.java:1313)
	at net.minecraft.server.v1_4_R1.World.tickEntities(World.java:1191)
	at net.minecraft.server.v1_4_R1.WorldServer.tickEntities(WorldServer.java:445)
	at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:580)
	... 4 more
2013-02-27 17:02:39 [SEVERE] This crash report has been saved to: /home/fourwonders/bukkit/serverdir/./crash-reports/crash-2013-02-27_17.02.39-server.txt