You have to get the IP address of your computer to port forward FMGO.
Start and End is 5003
To see what your Ip address is to your computer type CMD using Windows 7
type cmd in search box you should see cmd.exe click on it to launch
look for IPv4 Address 192.168.0.xxx
enter the last 3 digits in the IP addresson the Linksys Port Rang
it should restart your router once you save your settings and FMGO should work.
Lawfour, thanks for the advice but
I'm accessing the Linksys page via my Mac.
(For any mac users following this, you'll find your LOCAL (192.xxx etc) IPv4 in System Pref's -> Network)
The problem was user error (idiosy).
My wireless Linksys runs to my (hardwired) D-Link Router. It didn't occur to me that I ALSO needed to open the port on the D-Link. In my case 5003 to 5003, in conjuction with using the DLink's Local IP worked