Why dont you use one of the plugins?
Using the build in multiplayerstuff is a waste of time and effort.

(and you get better support from the plugin creators there)

Some small recent games of mine:
Griefer 4k http://damocles11.byethost9.com/griefer4k.html
Kobold 4k http://damocles11.byethost9.com/kobold.html
Cave 4k http://damocles11.byethost9.com/cave4k.html