[olpc-help] jabber enabled, but nobody in my neighborhood. Why?

[quixote]

I'm already on channel 1, and I upgraded to 653 before I started trying to do this.  I did find one really stupid error: I didn't have port 5222 open on my firewall.  :?   I gather that's the one jabber uses. 

However, opening it changed nothing.  I don't think it's an xo problem, because I just tried using jabber on my ubuntu machine and kept being told that "my user account could not be created" or some such error.  This is my first time using jabber, so I'm probably making a very basic error somewhere.  I've looked up the how-to on jabber.org, but so far no results.  More  :?