minecraft server crash

I was just playing a minecraft server, and the screen just crashed and this report came:

--- Minecraft Crash Report ----
// I let you down. Sorry :(

Time: 10/6/13 8:34 AM
Description: Ticking screen

java.lang.IllegalArgumentException: An objective with the name 'hbr1' already exists!
	at atj.f(SourceFile:159)
	at bcw.a(SourceFile:1144)
	at fu.a(SourceFile:99)
	at co.b(SourceFile:354)
	at bcw.e(SourceFile:98)
	at bcy.c(SourceFile:71)
	at atv.k(SourceFile:1173)
	at atv.S(SourceFile:663)
	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 atj.f(SourceFile:159)
	at bcw.a(SourceFile:1144)
	at fu.a(SourceFile:99)
	at co.b(SourceFile:354)
	at bcw.e(SourceFile:98)
	at bcy.c(SourceFile:71)

-- Affected screen --
Details:
	Screen name: bdk

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [bdi['leowonderful'/1638060, l='MpServer', x=8.50, y=66.62, z=8.50]]
	Chunk stats: MultiplayerChunkCache: 0
	Level seed: 0
	Level generator: ID 00 - default, ver 1. Features enabled: false
	Level generator options: 
	Level spawn location: World: (542,78,199), Chunk: (at 14,4,7 in 33,12; contains blocks 528,0,192 to 543,255,207), Region: (1,0; contains chunks 32,0 to 63,31, blocks 512,0,0 to 1023,255,511)
	Level time: 0 game time, 0 day time
	Level dimension: 0
	Level storage version: 0x00000 - Unknown?
	Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
	Forced entities: 1 total; [bdi['leowonderful'/1638060, l='MpServer', x=8.50, y=66.62, z=8.50]]
	Retry entities: 0 total; []
	Server brand: craftbukkit
	Server type: Non-integrated multiplayer server
Stacktrace:
	at bdd.a(SourceFile:284)
	at atv.b(SourceFile:1761)
	at atv.d(SourceFile:628)
	at net.minecraft.client.main.Main.main(SourceFile:101)

-- System Details --
Details:
	Minecraft Version: 1.6.4
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 59541624 bytes (56 MB) / 96706560 bytes (92 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 10817 (605752 bytes; 0 MB) allocated, 10817 (605752 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: Quadro FX 8