Rovi has many services, including guide data for DVR's though DISH does not use them for it. I think DISH uses Rovi or are allowed access to their patented features for other things also.
In a twist, DISH has acknowledged the Rovi patents, some others have not and have been or presently are being sued....
Rovi just completed the purchase and I believe the TIVO patents are still in affect with DISH. BTW some of those patents go away next year and a big one the next year. From reading the press release this is for other things that Rovi has owned. Separately the existing Tivo agreement acknowledges those existing patents and agreements even gives DISH cash now and some other concessions to both sides.