Minecraft java.lang.NullPointerException

2012-07-23 20:41:12 [WARNING] Failed to handle packet: java.lang.NullPointerException
java.lang.NullPointerException
2012-07-23 20:41:12 [INFO] [MCBans] Malibu23 has disconnected!
2012-07-23 20:41:12 [INFO] [OFC] Get Minecraft entity list error: null
2012-07-23 20:41:12 [INFO] [OFC] Get Minecraft entity list error: null
2012-07-23 20:41:12 [INFO] [OFC] Get Minecraft entity list error: null
2012-07-23 20:41:12 [INFO] [OFC] Get Minecraft entity list error: null
2012-07-23 20:41:12 [WARNING] Failed to handle packet: java.lang.NullPointerException
java.lang.NullPointerException
2012-07-23 20:41:12 [INFO] [MCBans] KingOfLol has disconnected!
2012-07-23 20:41:12 [SEVERE] java.lang.NullPointerException
2012-07-23 20:41:12 [SEVERE] 	at net.minecraft.server.World.tickEntities(World.java:1176)
2012-07-23 20:41:12 [SEVERE] 	at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:558)
2012-07-23 20:41:12 [SEVERE] 	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:459)
2012-07-23 20:41:12 [SEVERE] 	at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
2012-07-23 20:41:12 [SEVERE] Unexpected exception
java.lang.NullPointerException
	at net.minecraft.server.World.tickEntities(World.java:1176)
	at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:558)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:459)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)