Could you elaborate more on "doesn't work"?
What happens when someone tries to connect? On thier end and yours?
Do they simply time out, or is some error presented? Do you see any connection attempts on the POL console?
Can you ping the server from the client machine? And the client from the server? ("ping [IpAddress]" at a command prompt)
If you do a "netstat -a" on the host machine (at a command prompt) while the client tries to connect, can you see their connection?
Is there a router involved? If so, is it between the host and the client? Is port forwarding enabled on the router for port 5003 on internal connections?
What does the login.cfg file look like on the client machine?
Do normal networking functions work on the client/host, such as file sharing? Are both machines on the same subnet/network? I assume this is a peer-to-peer network? So no domains or active directory invovled.
Hmm, thats all I can think of now, but these are all the initial questions I would be asking myself to troubleshoot and isolate the problem.