Playlists

I have a playlist with more than 100 tracks.

When I save this playlist, at position 61 is mp3 number 6 (not mine) and the further rest of the playlist is removed.

I would like the option to

a) delete playlists b) edit playlists, thus add or remove tracks from saved playlists     and save as the same playlist.

Thanks.

[EatMe] - NL