If it's map music, then in your music.cfg file should read "media/music/Medieval1.mp3
You have it written as sounds where it should say music~
Also, your music files should be placed in the music folder of your media, not the sounds.
Maybe the music file is corrupted a bit and is not playing in the map maker. Have you tried deleting the music and redownloaded it altogether? Maybe there's something wrong with that specific file since it started to not work now. Maybe that'll do the trick?