Tvheadend

I am running xbmc as my front end (raspbmc specifically) with an HDHomeRun as my tuner on the backend. I followed the process to generate the strm files (which use the hdhomerun protocol) to access the tuner directly which works fine. However, when I try to access the same channel (frequency) through the tvheadend pvr add-on, I receive the message "Tvheadend HTSP Client No descrambler." I assume this is something I've done wrong rather than a bug in the program. For the record, this happens on a handful of channels, but I have a handful of channels working perfectly. Any thoughts or ideas are welcome.