I wouldn't worry about the custom icon settings until you get your hosting working.
Did Roger set you up with a crash.dangerdogz.com DNS host name? If not, have him do that, and then yes, run that DNS thing before you host.
As FB said, if you have a router you need to setup port forwarding for IL2 to port 21000 for your local computers local network ip. You can read how to do that at the portfowarding website. Look up your router and the IL2 FB game.
Then, test hosting. If you have a software firewall, make sure it lets the game through.. Disable it to test if you need to.