NmsBlock error

21:13:50 [SEVERE] java.lang.UnsupportedClassVersionError: MCPCPlusXNmsBlock_147 : Unsupported major.minor version 51.0
21:13:50 [SEVERE]at java.lang.ClassLoader.defineClass1(Native Method)
21:13:50 [SEVERE]at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
21:13:50 [SEVERE]at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
21:13:50 [SEVERE]at java.lang.ClassLoader.defineClass(ClassLoader.java:465)
21:13:50 [SEVERE]at com.sk89q.worldedit.bukkit.BukkitWorld$NmsBlockClassLoader.loadClass(BukkitWorld.java:228)
21:13:50 [SEVERE]at com.sk89q.worldedit.bukkit.BukkitWorld.<init>(BukkitWorld.java:146)
21:13:50 [SEVERE]at com.sk89q.worldedit.bukkit.BukkitUtil.getLocalWorld(BukkitUtil.java:50)
21:13:50 [SEVERE]at com.sk89q.worldedit.bukkit.BukkitPlayer.getWorld(BukkitPlayer.java:132)
21:13:50 [SEVERE]at com.sk89q.worldedit.bukkit.WorldEditListener.onPlayerInteract(WorldEditListener.java:121)
21:13:50 [SEVERE]at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
21:13:50 [SEVERE]at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
21:13:50 [SEVERE]at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
21:13:50 [SEVERE]at java.lang.reflect.Method.invoke(Method.java:597)
21:13:50 [SEVERE]at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
21:13:50 [SEVERE]at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
21:13:50 [SEVERE]at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
21:13:50 [SEVERE]at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
21:13:50 [SEVERE]at org.bukkit.craftbukkit.v1_4_R1.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:178)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.PlayerInteractManager.interact(PlayerInteractManager.java:376)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.PlayerConnection.a(PlayerConnection.java:657)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.Packet15Place.handle(SourceFile:58)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.NetworkManager.b(NetworkManager.java:290)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.PlayerConnection.d(PlayerConnection.java:113)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.ServerConnection.b(SourceFile:39)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.DedicatedServerConnection.b(SourceFile:30)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:598)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:224)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
21:13:50 [SEVERE]at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)

This error occurs everytime I start a server, right after I installed worldedit. It's something to do with NmsBlock, which came with worldedit. And I have no idea how to fix it...

 

Something is out of date! Is this definitely the latest version of WorldEdit?
-Capy

 

Locked. This is not a CraftBukkit server, seek out the mod makers for help.