Long time lurker here, so I thought I'd document at least one of my most recent woes.

After purchasing a new dual tuner Australian Tivo, I thought I'd go back and try and resurrect my original series 1 oztivo.

The crux of the problem here is that the image I had was the 2006.11.06 1.6.2 image, which pre-dates the emulator move from minnie.tuhs.org to www.oztivo.net. (In retrospect, I should have just downloaded the new image, but at the time my internet access was shaped and I didnt have a cd to burn it to anyway...)

So the Guided Set Up fails when it gets to First Setup Call and returns service unavailable. Luckily at this stage you can get in via telnet and run the following commands to update the emulator address:

$ rw
$ pico /etc/oztivo.conf

When pico opens the file change the emulator values to:
emulator=www.oztivo.net
emulatorport=9090

$ ro

Then reboot and try the First Setup Call again.

Worked for me! Hope it'll help someone else.