I tried both with the box's actual IP, as well as 192.168.0.5 verbatim. The first yielded the same set of results (although logs clearly show it connecting over the ethernet interface rather than loopback); the second yielded "This zone is unavailable", which is about what I expected but figured was worth a shot
Just for fun, I also tried changing the port to 9000 since it seems to like that one (the UDP world server port seems to be non-configurable). Same results there as well.