How To Manage Sound Objects In Large Presentation

Part of a larger presentation I've made, there is some background music. What happens is an XML file is read to get a file to play. It plays. When it finishes, it reads the XML again to get the new file. It can also stop when a video plays elsewhere in the presentation then I pick it up where it left off and start the process again. Trouble is, the presentation randomly stops. The music stops and the slides in the presentation stop. The music and slides come from a single XML file. There's also a third part of the presentation (a text crawler) that never stops.

This comes from a totally separate XML file. I never get an error, the presentation just stops on a slide and no more music plays, but the crawler keeps crawling. I've removed all the code for the music and it runs perfectly so it's obviously related to how the music is managed. So, finally, my question is how do I manage sound objects? If I need to create new objects for each sound I load and play, I'll need to do manage the sound from a single function, right? Something like:

Code:
function whatever():void {
if song is not loaded {
read xml, load and play song;
} else if video is playing {
pause the song;
} else if video has stopped playing {
resume song;
}}