Glad that you have made it this far
[INFO] Starting minecraft server version 0.2.5_02
[INFO] loading properties
[INFO] startong minecraft server on x.x.x.x:25565
[WARNING] ****FAILED TO BIND TO PORT!
[WARNING] The exception was: java.net.BindException: Cannot assign requested address
[WARNING] Perhaps the server is already running on that port?
You put your public IP as "server-ip"? As far as I know, it's not supposed to be there
Mine looks like this (excluded server-port for security reasons):
As you can see, I have left the server-ip field blank (and I'm running this on my gateway as well)
If not, you might be running a minecraft server already, you can check this by running
ps aux | grep minecraft_server
The output will be something like this:
username 5186 1.3 3.9 1175888 126912 pts/1 Ssl+ 11:06 0:16 java -Xmx1024M -Xms1024M -jar minecraft_server.jar nogui
All you need to do if you are running this on your gateway is to log on the webinterface and goto "Incoming" on firewall and set e.g. port 25565 to be open
As you know, people would only need you public IP to access the server if you run it on a default port, so if you want to be a litte more secure, you can set a different port in the server.properties.
EDIT: I realised now that the stuff with "ps aux" and such is not really relevant when you don't run it in the background, but oh well, i'll leave it in for future reference