Same music over different presentations

I use PPT 2002, and like to have others use PPT Viewer 2003.
I've got a "table of contents" PPS and added a music page
so that students can click on one of 10 music files and have it
play over the (different) presentation that they call up. Everything
is in the same folder and worked great.
Then I added a new presentation (a file I had created last year).
Everything still works with the previous files, but when I call up to
the "new" file the music stops. If I hit escape to get back to the table of contents show, the music picks up from where it left off.
I figure this must be a simple switch on the "new" file that says
"stop the previous music when opening this file" but I can't find it.
Any ideas?
--
Pete

It now works - sometimes
The set up is:
Table of Contents
goes to several other seperate presentations
or to Music page
Music page
goes back to table of contents
or to "Break page"
If I start the music and go directly to the break page, the music stops
and then comes back on again when I exit break page (with escape)

but, if I start the music, go back to the table of contents page,
then back to the music page, then to the break page
the music keeps on playing

One backward irrelevancy:
When the table of contents file is 1st entered Pink Floyd starts automatically
But when the music page starts up, "stop previous sound" is in the transition
and stops PF. But of course it is not now stopping any other music,
rather it seems to be enabling it to continue.

--
Pete