Try adding your router IP to the DNS and Gateway settings. Think your router IP is not the usual 192.168.1.1...
I added a Roamio and did not add in the DNS and Gateway IP to my wireless. I did with the Series 3.
Series 2 (80 hrs,PLS, Retired)
TiVo HD 1TB (157 HD Hrs, PLS, "S3HD")
Roamio, Oh Roamio!
The TiVo Apocalypse begins on Sat 2013 Feb 16 00:00 GMT!