Simple install on Ubuntu

Hi folks.

I've tried umpteen config mods and still don't seem to have a working server so, here I am, hoping for some help.

The system is a fresh install of ubuntu 11.10 server.

I installed the server with apt-get install ejabberd. I edited /etc/ejabberd/ejabberd.cfg to include this...

There's a DNS A record for the server, and the router is configured to forward 5222, 5269 & 5280 to the server machine.

I run service ejabberd start and then do ejabberdctl status and get

Glenlivet is the host name in the local network.

If I try to register a user with ejabberctl register username jserv.drsimon.co.nz password I get
Can't register user username@jserv.drsimon.co.nz at node ejabberd@glenlivet: not_allowed

So folks... what have I got wrong and how do I go about fixing it?

Thanks.

Simon.