ScoreBoard health objective crashes game

Client> u: Ticking memory connection
Client> 	at jm.b(SourceFile:39)
Client> 	at bhc.b(SourceFile:84)
Client> 	at net.minecraft.server.MinecraftServer.r(SourceFile:488)
Client> 	at net.minecraft.server.MinecraftServer.q(SourceFile:405)
Client> 	at bgz.q(SourceFile:124)
Client> 	at net.minecraft.server.MinecraftServer.run(SourceFile:339)
Client> 	at gr.run(SourceFile:582)
Client> Caused by: java.lang.NullPointerException
Client> 	at z.a(SourceFile:175)
Client> 	at z.a(SourceFile:196)
Client> 	at ht.a(SourceFile:527)
Client> 	at aa.b(SourceFile:123)
Client> 	at net.minecraft.server.MinecraftServer.a(SourceFile:705)
Client> 	at jj.a(SourceFile:751)
Client> 	at cx.a(SourceFile:29)
Client> 	at cj.b(SourceFile:64)
Client> 	at jj.d(SourceFile:56)
Client> 	at jm.b(SourceFile:35)
Client> 	... 6 more
Client> 2013-04-25 17:00:55 [SERVER] [SEVERE] Encountered an unexpected exception u
Client> u: Ticking memory connection
Client> 	at jm.b(SourceFile:39)
Client> 	at bhc.b(SourceFile:84)
Client> 	at net.minecraft.server.MinecraftServer.r(SourceFile:488)
Client> 	at net.minecraft.server.MinecraftServer.q(SourceFile:405)
Client> 	at bgz.q(SourceFile:124)
Client> 	at net.minecraft.server.MinecraftServer.run(SourceFile:339)
Client> 	at gr.run(SourceFile:582)
Client> Caused by: java.lang.NullPointerException
Client> 	at z.a(SourceFile:175)
Client> 	at z.a(SourceFile:196)
Client> 	at ht.a(SourceFile:527)
Client> 	at aa.b(SourceFile:123)
Client> 	at net.minecraft.server.MinecraftServer.a(SourceFile:705)
Client> 	at jj.a(SourceFile:751)
Client> 	at cx.a(SourceFile:29)
Client> 	at cj.b(SourceFile:64)
Client> 	at jj.d(SourceFile:56)
Client> 	at jm.b(SourceFile:35)
Client> 	... 6 more
Client> 2013-04-25 17:00:55 [SERVER] [SEVERE] This crash report has been saved to: C:\Users\Harvest\AppData\Roaming\.minecraft\crash-reports\crash-2013-04-25_17.00.55-server.txt
Client> 2013-04-25 17:00:55 [SERVER] [INFO] Stopping server
Client> 2013-04-25 17:00:55 [SERVER] [INFO] Saving players
Client> #@?@# Game crashed! Crash report could not be saved. #@?@#
Client> 2013-04-25 17:00:55 [SERVER] [INFO] Stopping server
Client> java.lang.IllegalArgumentException: Empty string not allowed
Client> 	at cg.<init>(SourceFile:15)
Client> 	at bu.a(SourceFile:77)
Client> 	at asa.e(SourceFile:186)
Client> 	at asa.b(SourceFile:112)
Client> 	at alh.a(SourceFile:88)
Client> 	at alh.a(SourceFile:76)
Client> 	at jb.a(SourceFile:642)
Client> 	at jb.a(SourceFile:627)
Client> 	at net.minecraft.server.MinecraftServer.a(SourceFile:263)
Client> 	at net.minecraft.server.MinecraftServer.k(SourceFile:283)
Client> 	at bgz.k(SourceFile:234)
Client> 	at net.minecraft.server.MinecraftServer.run(SourceFile:372)
Client> 	at gr.run(SourceFile:582)
Client> AL lib: (EE) alc_cleanup: 1 device not closed
Game ended with bad state (exit code -2)