Hi, sorry if my thread is obvious.
I've read and followed all the threads in the skin subforum with no success.

1. copy fbskin file to sd card (also tried phone's internal memory)
2. choose skin
3. add more / open
4. select fbskin file

After selecting the file, the app returns to the choose skin screen with no change at all. Nothing but the two default skins. No user skins found.
This happens with all the examples in the skin subforum, even with the Spoon Test Skin.

My phone is Lumia 640 LTE, with windows phone 8.1 update 2

Thanks in advance!