It doesn't work in Chrome because you're playing that music as a positioned sound, and the rest of the project appears to use ordinary playback rather than positioned sounds, so that looks like a mistake. (You need to set the listener object etc. before positioned sounds will play correctly.) If you switch it to an ordinary play action it works fine.
The error when running with Firefox was a bug; should be fixed in the next build, but it still won't play at a position due to a workaround we have to use to get around a Firefox bug.
IE doesn't play because you don't have .m4a versions of your music tracks.