OK, this puzzles me. I'm using a standalone installation on ubuntu LTS 10.04.
Both the port redirection (UPnP) and the web forward service thinks the ip address is 127.0.0.1, instead of the correct one, 192.168.1.100.
The only thing I can think is that I have several network cards, but eth1 (not eth0) is the one in use.
Sadly I don't understand java, so I can't really see where the logic fails.
I've also tried to specify --host=192.168.1.100 with the same result - e.g. subsonic using 127.0.0.1 instead.
Setting all the other interfaces to 'down' and restarting subsonic does not help.