Normally when a program that Norton doesn't recognize tries to access the internet, it asks you what you want to do.
I'm currently running NIS 2008, but have used Norton for years.
Go into Internet Security. You should see a tab there called Norton Internet Security, and then click on Settings.
You should see something called Norton Internet Security Options. Click it, and open up the settings for the Personal Firewall and then click on Program Control.
You should see a list of every program installed on your computer that Norton has encountered. Look for Starfleet Command, and you should see a drop down window next to it that allows you to configure the game's access to the net. Make sure it's set to Allow.
Then again, what I've done in the past, is just disable the firewall for the time I'm gonna be flying, and then re-enable it when you're done. I do this because sometimes if my firewall is on while I'm flying, and my game either crashes or I freeze up and have to log off the server and back on, my firewall doesn't allow my computer and game server to communicate properly, and the game server will think I'm still online.