As I stated in another thread on this forum, I have the same kind of problem. The streaming from my Windows 7 pc works just fine, I can make playlists just fine, but my mobile app on my Samsung Galaxy S4 seems to be extremely sparse. I can only pause, skip along my pre-made playlist and control volume from my phone, not browse any of the folders I have added to my media library on my pc, not from the mobile change subtitles as the pictures on your Google play store page would indicate; there's simply no options to do anything else inside the mobile app.
Added is a screenshot of how my mobile app looks like on my phone.
I have tried reinstalling the app on both my phone, pc, turning off the firewall, but nothing changes on the app itself, ist just works as it did before anyway.