Please read the other comments. It means there might be an issue you're missing. Permissions to access certain files, etc. or RU sure they're audio files you're trying to add to the list.
Hey got a great idea. Why not get a backup player like iTunes. It'll organise all your music into folders like artist>album so it's easy to find & access & play. You'd just share the iTunes Music library then for this effect. See hints here:
Albumwrap/iTunes Within iTunes you can create your own playlists or import them from LW's media player. If you disable LW's media player then iTunes will play them instead.