Then you've most likey entered the wrong IP and/or port in your servers.txt

If you are running it on the same PC as you're trying to connect from, use 127.0.0.1 as IP. If you want your server to be available from the internet, make sure that you have the NAT set up forrectly.

Also, make sure that you don't have a firewall blocking it.

Alot of info about NAT and other things you should be aware about can be found in this thread: http://www.toribash.com/forum/showthread.php?t=1107