What system are you running...
i Had exactly the same problem and it was the built in firewall on xp, Disable it and youll pick up you server.
Plus does your ISP change the ip address when you log on.Im with BT and everything i log on i get a different ip address. Otherwise people will never find your server. I use Http://www.no-ip.com. This company offers the chance to have a static name but using your different ip . Youll have to download a bit of software that allows their server to pick your new ip address up.
Theirs nothing wrong with your conf file...
To disable the firewall
Control panel ----->network connections-----> choose what ever you use to connect to the internet with ---->Properties-----> advanced----. top of the box is internet firewall uncheck the box...
Then try a get someone to ping your server. if you dont know what your ip address is.
Open the Dos command and type in IPCONFIG that will give you your curreent ip. Get someone to ping it....type in like this http://127.0.0.1 (the number being the ip address).
Hope this helps..