I got mine set up quickly with little fuss on Windows XP, files on an Airlink NAS with the share name "NetDrive".
Subsonic set up the port forwarding after I changed the port from the default.
The mapped drive didn't work, but as soon as I got the network path correct, I was connected. Mine looked like this:
//Netdrive/Storage/C/Music
with "Netdrive" being the share name of the NAS (found it in the NAS config)
Granted, it's not the same setup but, judging from many of the posts here, getting the network path correct is the key.
Then I used a DynDNS URL directed to the correct port:
http://xxxx.homeip.net:8080
Works great. My wife's Eris is throwing some network errors, but I have just started working on it.