My WD NAS has these default folders:
/Public <- shared by default via SMB for any user
and in it are
/Shared Music
/Shared Pictures
/Shared Videos
So, once I figured out you need (for whatever reason) a password to access your share, I added the user chet/chet for the share /Public. Now the subfolders are visible but there's nothing in it.
When I access the very same folder from another PC on my network I see all the subfolders and can play music from any MP3 album in there. Why not from VLC?