Thanks for the screen shot you sent! It actually seems to show the phone is where you have it going on your end, and not the card, at least as viewed from windows PC? I created a folder in that same location and it fired up and WORKED! deleted the SD card folder still working!
The Galaxy S6 has only one SD slot of course. Not sure where that name came from that my ES shows - perhaps a volume label at sd initialization? though I didn't assign it or remember it coming up. There seems to be a lot of confusion on SD cards and android including different versions of Android - beyond my level of knowledge - googling I found similar things such as the following... not sure what all it is about, perhaps you will. http://android.stackexchange.com/questions/39542/confused-by-the-many-locations-of-the-virtual-sdcard
As I said it is working when I make the \VRTourviewer from windows PC on the root of the phone, or at least what appears to be the phone's root according to Windows USB access, and NOT on the SD card, as it seems you intended perhaps.
On the tour itself, I was excited to see it working nicely and the lense flairs add a nice effect. I did notice, it does seems to ignore when jumping to a pano the starting view points I had set, and also the starting viewpoint of first pano I set - it seems to take a mid point or a certain cube face and that's it (about middle of source pano).
Could you give us a way to select subfolders under that \VRTourviewer, ideally on SD versus main phone but either is ok for now? That would allow a simple menu construct and let us also see the path info more clearly.