Bukkit

What steps will reproduce the problem?

1. Downloaded the latest version of MobDisguise.
2.Everything worked well... But...
3.When I use fx: /md sheep it says: An internal error occured while attemptinh to perform this command

What is the expected output? What do you see instead?

I hoped I could be disguised as a sheep.
It didn't work...

The server says:
21:26:34 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'md' in plugin MobDisguise v1.81
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:185)
at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:504)
at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:911)
at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:824)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:806)
at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:44)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:282)
at net.minecraft.server.NetServerHandler.d(NetServerHandler.java:111)
at net.minecraft.server.ServerConnection.b(SourceFile:35)
at net.minecraft.server.DedicatedServerConnection.b(SourceFile:30)
at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:578)
at net.minecraft.server.DedicatedServer.r(DedicatedServer.java:215)
at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:495)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:428)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:818)
Caused by: java.lang.NoSuchFieldError: f
at me.desmin88.mobdisguise.utils.PacketUtils.packetMaker(PacketUtils.java:146)
at me.desmin88.mobdisguise.utils.PacketUtils.disguiseToAll(PacketUtils.java:61)
at me.desmin88.mobdisguise.commands.MDCommand.onCommand(MDCommand.java:216)
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
... 15 more

What version of the product are you using?

v1.81

Do you have an error log of what happened?

I think it would be too long, if I paste it again :-)

Please provide any additional information below.

I've read the FAQ...
I do something wrong... Probably, but what?
And how do I fix it?
I hope you can help me.

~Biuer