Could you please remove the UnsupportedOperationException in PermissionBukkit? I want to use the world feature from the other permission plugins too, but i cant, because i need to set world to null for PermissionsBukkit. Please just ignore the world...

if (world != null) {
throw new UnsupportedOperationException(getName() + " does not support world based groups.");
}

These Commands are in wrong order: The player needs to be written before the group.... failed ;)

Change line 191 : return plugin.getServer().dispatchCommand(ccs, "permissions player addgroup " + group + " " + player);
To : return plugin.getServer().dispatchCommand(ccs, "permissions player addgroup " + player+ " " + group);

Change line 199 : return plugin.getServer().dispatchCommand(ccs, "permissions player removegroup " + group + " " + player);
To: return plugin.getServer().dispatchCommand(ccs, "permissions player removegroup " + player+ " " + group);

Good catch on the transposed player/group command.

As for the UnsupportedOperationException, perhaps we can give a warning in the server log instead of aborting the operation. Just a thought.

It's up to you, but that would me really nice :)