I had a 522 connected to only a single Sat feed for a few weeks and it just worked fine. Just don't expect PIP or multi-tuner/Recorder type functions to work. FYI - I don't believe that setting the 522 to Single MODE will do anything for you with only the one Sat input.
I'll assume that basic recording works for shows you're watching? If not you got bigger problems than timers. Anyway, check your DVR set-up preferences and see how you have them configured.Check the following: Select Menu>Preferences>Record Plus and set Activation=Enable and Preference=TV1. Can you set a timer now?