I had the same problem. The music kept playing even after I sold it in buy mode and deleted it. I hope this gets fixed; I would love to have this in my game again.
Yeah i think i had the same problem with it in my game, except that one song started playing and then stopped after like 20 seconds and then i got this strange sort of buzzing sound, a bit like the UFO in the game that continued even whilst i was turning the whole game (sims2) off?....although the sound may have been because the music volume in my game is very low, and that sort of thing happens with my music and stuff too.
Anyway its a great idea and an awesome addition to my game...other than that problem lol. Thanks!!