Finally purchased full version for my android tablet- a generic allwinner 7 inch device. Downloading bjf files or loading them from sd card has proven tricky at best. I've followed instructions they load and then after I shut off the device the next time they are supposedly there in the files under the file manager, but they are not in the list to play. Suffice it to say that this must be a permissions problem, not necessarily with the software, but perhaps the device and also the way google android is now treating write permissions of the owner of the device.
This device is supposed to be rooted. I have finally managed to load all of the custom bjf files and turn off and on my device. I'll keep you informed if they disappear again. I used my original rooted file manager to transfer from sd card and it seems to be working now. I also exported the apk and reinstalled via pc, making sure it was to the root. This seems to have done the trick.
I'm also having difficulty with the background music playing. Does the android version prefer mp3 or ogg files? I'll convert to whichever it likes. We noticed the pc version seemed to prefer all one kind - so no mixing of ogg and mp3 in a playlist.