I have the same problem.
I have registered the Premium version and set up the link to my movie folder but still cannot select a movie from the phone app.
This is the last time I pay for software before it proves it works.
I can run a movie from my PC through chromecast using a free android app RS File Explorer.
This app doesn't even require any software except file sharing to be running on the PC.
$35.00 US down the drain.