Use a static IP.
Set network settings to include the DNS and Gateway to your router IP.
Check the DVR preferences on your Tivo.com account to be checked.
Reboot the Tivos and router.
Make a Tivo connection on all your Tivos.
Make sure your Tivos all have the same Media Access Key.
Doing these should get it working.
Series 2 (PLS, sold)
TiVo HD 1TB (157 HD Hrs, PLS, "652")
Roamio! Oh, wait, Its Juliet!
OTA! OTA! OTA!
The TiVo Apocalypse begins on Sat 2013 Feb 16 00:00 GMT!