Hmm, I found that running my game in Firefox rather than Chrome works, and the sounds + music play fine, but at the start of the game where the music is played, this error pops up...
<img src="https://dl.dropboxusercontent.com/u/7765312/AudioErrorFirefox.png" border="0" />
@Ashley , I can't seem to recreate this in a new capx. I made a new project and added the exact same Music I'm using and played it in the same way, but no error message. I'll proceed to skin down my project and see what it might be, but before I go forth with that, does this error message help at all in knowing what to do?