Did you use "/md Herobrine" or "/md Notch"? Use "/md p Herobrine" or "/md p Notch" instead :D and of course do it without quote XD
I installed BukkitContrib and get: [SEVERE] Could not load 'plugins\MobDisguise.jar' in folder 'plugins': java.lang.NoClassDefFoundError:...
[SEVERE] Could not load 'plugins\MobDisguise.jar' in folder 'plugins': BukkitContrib org.bukkit.plugin.UnknownDependencyException: BukkitContrib...
Separate names with a comma.