Hello because I have been playing Minecraft for a long time I decided to make a BUKKIT server I set up all the files correctly and have some plugins:

I invited 1 of my friends to join and gave him the IP he said it said "unknown host" so I looked up about it and somebody said if your IP begins with "192" then the IP is local so only people in your network can use it by the way I don't use Hamachi or port forwarding I use µTorrent, anyway so the person said go to "whatsmyip.com" or something similar to that so I did and there was a different IP so I put that into my BUKKIT files in the "server.properties" where it said IP saved it and double clicked "run" then a couple of seconds later it said "FAILED TO BIND TO PORT! The exception was: java.net.BindExeption: Cannot assign requested address: bind, perhaps a server is already running on the port?" And then I tried to join my server and it said "unknown host" because before I changed the IP I could join it but now I cant even do that. I'm sorry this is long just im really stuck. PLEASE HELP me.

Any Suggestions?