WorldEdit Error

2012-09-14 19:41:53 [SEVERE] java.lang.NullPointerException
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.Chunk.a(Chunk.java:387)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.Chunk.a(Chunk.java:354)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.World.setRawTypeId(World.java:270)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.World.setTypeId(World.java:342)
2012-09-14 19:41:53 [SEVERE] at org.bukkit.craftbukkit.block.CraftBlock.setTypeId(CraftBlock.java:92)
2012-09-14 19:41:53 [SEVERE] at com.sk89q.worldedit.bukkit.BukkitWorld.setBlockType(BukkitWorld.java:127)
2012-09-14 19:41:53 [SEVERE] at com.sk89q.worldedit.EditSession.rawSetBlock(EditSession.java:230)
2012-09-14 19:41:53 [SEVERE] at com.sk89q.worldedit.EditSession.flushQueue(EditSession.java:677)
2012-09-14 19:41:53 [SEVERE] at com.sk89q.worldedit.WorldEdit.handleCommand(WorldEdit.java:1278)
2012-09-14 19:41:53 [SEVERE] at com.sk89q.worldedit.bukkit.WorldEditPlugin.onCommand(WorldEditPlugin.java:197)
2012-09-14 19:41:53 [SEVERE] at com.sk89q.bukkit.util.DynamicPluginCommand.execute(DynamicPluginCommand.java:52)
2012-09-14 19:41:53 [SEVERE] at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:168)
2012-09-14 19:41:53 [SEVERE] at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:492)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:878)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:825)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:807)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:44)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.NetworkManager.b(NetworkManager.java:276)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.NetServerHandler.d(NetServerHandler.java:109)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.ServerConnection.b(SourceFile:35)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.DedicatedServerConnection.b(SourceFile:30)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:581)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.DedicatedServer.q(DedicatedServer.java:212)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:474)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:406)
2012-09-14 19:41:53 [SEVERE] at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)