Myworld crash

2013-01-25 14:26:05 [SEVERE] java.lang.NoSuchMethodError: net.minecraft.server.v1_4_R1.EntityHuman.getBukkitEntity()Lorg/bukkit/entity/HumanEntity;
2013-01-25 14:26:05 [SEVERE] 	at com.bergerkiller.bukkit.mw.PlayerData.load(PlayerData.java:291)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.PlayerList.a(PlayerList.java:143)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.PlayerList.a(PlayerList.java:67)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.PendingConnection.d(PendingConnection.java:130)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.PendingConnection.c(PendingConnection.java:45)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.DedicatedServerConnectionThread.a(DedicatedServerConnectionThread.java:44)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.DedicatedServerConnection.b(SourceFile:29)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:598)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:224)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
2013-01-25 14:26:05 [SEVERE] 	at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)
2013-01-25 14:26:05 [SEVERE] Encountered an unexpected exception NoSuchMethodError
java.lang.NoSuchMethodError: net.minecraft.server.v1_4_R1.EntityHuman.getBukkitEntity()Lorg/bukkit/entity/HumanEntity;
	at com.bergerkiller.bukkit.mw.PlayerData.load(PlayerData.java:291)
	at net.minecraft.server.v1_4_R1.PlayerList.a(PlayerList.java:143)
	at net.minecraft.server.v1_4_R1.PlayerList.a(PlayerList.java:67)
	at net.minecraft.server.v1_4_R1.PendingConnection.d(PendingConnection.java:130)
	at net.minecraft.server.v1_4_R1.PendingConnection.c(PendingConnection.java:45)
	at net.minecraft.server.v1_4_R1.DedicatedServerConnectionThread.a(DedicatedServerConnectionThread.java:44)
	at net.minecraft.server.v1_4_R1.DedicatedServerConnection.b(SourceFile:29)
	at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:598)
	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)