check the 'tuners 5 and 6 not authorized' thread in the roamio forum area.
Most of the people are having issues with old firmware on sa/cisco cards, but the motorola also has a minimum firmware level that is needed. It is also possible that your TA will only work with 4 streams at a time.
Roamio Pro, wired ethernet
Mini using MOCA (from the Pro)
on Cablevision Raritan Valley system (Central NJ)
w/ Cisco PKM803 CableCARD on firmware 22.214.171.1241
*** 2013 newbie to Tivo ***