Hi Gary as you probably know already, Tyros and PSR's have to be set in the right "mode" for finding the file types you need. For instance if it's in the mode to look for styles, it will only find .sty/.prs (and the other style extensions) files. It will ignore the other extension types- registrations, voices etc.
Hence the need to press a song button first - to get it in the right mood
I've come across some difficulties before where files present on a stick formatted to FAT on my PC would not be recognised or would be read as corrupted on Ty2.
That was solved after reformatting on Ty2 and copying the files back in.
No guarantees it'll be the same in this case
John