did you bind the IP address to the same one as your webserver (which is reachable)?
Maybe you have the Win2003 firewall enabled and need to open port 5222 to enable XMPP clients to connect. The old-SSL, Web-Admin and Proxy ports are not needed for the basic connectivity.
If you “netstat -a” at comman prompt on that server, do you see it listening on correct port?
From the WAN, can you telnet to “servername 5222” and have it “answer”?
Is there a router or firewall between server and WAN? Is port forwarding enabled on that internetworking device to get tcp/5222 and or tcp/5223 and or tcp/5269 to that internal IP?
You said that the Windows firewall is not running, so OK. Any third-party firewall (or other security software) on that machine?