Which version of the Tvheadend package are you using?
I the only one I have managed to use successfully with my PCTV stick is one you compile yourself using the instructions posted by HarryL. I also found that I needed the access control file (both mentioned in OSMC RC Unable to install TVHEADEND - #49 by DBMandrake) and some firmware files I eventually found elsewhere on the net. I have failed to get my WinTV-HVR-900H working, possible due to the firmware files that worked on RASBMC.