Undo Error

[Spezialeinheit]

2012-06-03 17:14:41 [INFO] [HawkEye] DEBUG: Starting undo of 6830 results
2012-06-03 17:14:41 [INFO] [HawkEye] DEBUG: Undo complete, 6830 edits performed
2012-06-03 17:14:45 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'hawk' in plugin HawkEye v1.0.7b
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:42)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:166)
at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:630)
at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:864)
at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:822)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:800)
at net.minecraft.serverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:141)
at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:33)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:103)
at net.minecraft.serverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:83)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:637)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:510)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
at uk.co.oliwali.HawkEye.Undo.(Undo.java:35)
at uk.co.oliwali.HawkEye.commands.UndoCommand.execute(UndoCommand.java:21)
at uk.co.oliwali.HawkEye.commands.BaseCommand.run(BaseCommand.java:75)
at uk.co.oliwali.HawkEye.HawkEye.onCommand(HawkEye.java:257)
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:40)
... 14 more