Remove the Server IP, it'll default to the correct one if you leave it blank. You're going to have to use two different IPs to connect, one that you give to people who are outside your network, and one that you give to people that are inside your LAN. The one you give to outside people is your external IP, you can get it by googling "What's my external IP." and google just tells you. To connect to your own server you're going to use your internal IP which is given to you by your router. Open CMD and type "ipconfig," look for the IPv4. It'll look something like 192.168.1.x. Another trick is to use 127.0.0.1, which will always connect directly to your own computer. If your server is up and running correctly then 127.0.0.1 will always connect to it.
Edit-
Scratch my first instructions, I didn't read that you were using Hamachi. In that case you will fill in the IP= section with the IP that Hamachi gives you, which you probably already did. Test direct connect with 127.0.0.1 and see if you're able to get in.
Edit2 -
If you or your buddies are still not able to connect give this a shot. http://www.mpgh.net/forum/386-minecraft-server-advertising/247750-how-make-your-own-minecraft-server-hamachi.html