Just because subsonic can't see your router doesn't mean it isn't working.
You should be able access subsonic locally (i.e. on the machine subsonic is running on) by going to
http://localhost:[portnumber]. .e.g.
http://localhost:4040
Machines on the same network will be able to access it too via your local network IP address. e.g.
http://192.168.1.100:4040/
This is assuming that a firewall on the machine running subsonic isn't blocking access.
If subsonic cannot setup port forwarding automatically using uPnP then you should setup port forwarding manually. Look at your router's instruction manual to find out how to do this.