Trying to run a new server, having probs. Please help

Hello everyone.

I am having a really frustrating time trying to get my server up and running. I am using Port Map and when ever I try to run the server, it says ** FAILED TO BIND PORT! Perhaps a server is already running on that port?

I've tried to go to Activity Monitor and quit Java, but when I open up the terminal thing Java comes up again.

I've also tried to delete the ip from server.properites and then run it, and that has worked, although what is my ip now?

I really need help. Someone please respond!

Thanks.