02:44:32 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'md'
in plugin MobDisguise v1.63
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:37)
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:129)
        at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:352)
        at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:737)
        at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:701)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:694)
        at net.minecraft.server.Packet3Chat.a(Packet3Chat.java:33)
        at net.minecraft.server.NetworkManager.b(NetworkManager.java:226)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:89)
        at net.minecraft.server.NetworkListenThread.a(SourceFile:105)
        at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:465)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:422)
Caused by: java.lang.NoSuchFieldError: b
        at me.desmin88.mobdisguise.utils.PacketUtils.packetMaker(PacketUtils.java:132)
        at me.desmin88.mobdisguise.utils.PacketUtils.disguiseToAll(PacketUtils.java:59)
        at me.desmin88.mobdisguise.commands.MDCommand.onCommand(MDCommand.java:176)
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:35)
        ... 12 more
02:44:41 [WARNING] Task of 'MobDisguise' generated an exception java.lang.NoSuchFieldError: b
        at me.desmin88.mobdisguise.utils.PacketUtils.packetMaker(PacketUtils.java:132)
        at me.desmin88.mobdisguise.utils.PacketUtils.disguiseToAll(PacketUtils.java:59)
        at me.desmin88.mobdisguise.utils.DisguiseTask.run(DisguiseTask.java:26)
        at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:137)
        at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:439)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:422)