A few quick ideas to try.
Make sure your Playlist files end in .m3u and all have a unique name within the first 12 characters (?)
Make sure your Playlist files reside in the main Playlist folder or reside somewhere within the main Music folder.
Only Music or Card mode can access Playlists.
AND, make sure your music files have at least one unique character (number, letter) within the first 7 characters of the filename.
