I'm on the site using the following structure to store data:

data - data storage folder
data / lettername - a folder by alphabet letter
data / lettername / artistname - folders by artist name
data / lettername / artistname / gallery - storage photo files artist
data / lettername / artistname / discography - folder by album artist
data / lettername / artistname / discography / albumname - Album folder
data / lettername / artistname / discography / albumname / cover - album covers are the files
data/lettername/artistname/discography/albumname/album_mp3 - archive file for download album
data/lettername/artistname/discography/songs_mp3 - mp3 songs files

Following problem:
With such a structure is easy to mp3 files available for download, add and listen to playlists.
On the pages of the album and song files do NOT PLAY in player.

In what may be the reason? Thanks!

P.S.Data = /images/phocagallery (in configuration MC)
File path song (name field) etc. - L/LedZeppelin/discography/1969-LedZeppelinI/songs_mp3/01-Good Times Bad Times.mp3

See here and add songs to playlists
Listen playlist