SqueezeCenter add-on gives error "Failed to Connect" upon clicking SETUP

[deal]

I had SqueezeCenter 7.2.1 running successfully on my ReadyNAS NV+ (1GB RAM, 2TB, firmware 4.1.4), however it would occassionally delay when streaming some music to my Transporter. I thought I might try the next release of SqueezeCenter, 7.3, to see if that problem had been fixed. Yesterday I uninstalled SqueezeCenter using the REMOVE button on the Streaming Services tab in FrontView, and I uploaded the SqueezeCenter 7.3 binary release that just came out from Logitech. I rebooted the ReadyNAS and found the add-on successfully installed in FrontView. However, when I click the SETUP button to setup SqueezeCenter the resulting webpage says "Failed to Connect" "Firefox can't establish a connection to the server at xxx.xxx.xxx.xxx:9000". In the address bar of the error, the right IP address shows up with the correct port number, for example xxx.xxx.xxx.xxx:9000. This is exactly the same IP address and port that I had used successfully with SqueezeCenter 7.2.1. I tried using the URL in IE 6 and got the "The page cannot be displayed" message.

Can anyone help shed some light on my problem? Am I missing a step or doing something wrong?

TIA
David