Media files prevent Flash from fully loading externalXML file

Im trying to debug a flash widget we created, and it loads fine on the 20 odd
computers we tested on EXCEPT for one computer where, the application doesn't
load an external XML file that calls for 3 small mp3 files and a FLV file to
load as well.

In a debugger, we noticed that when it tried to load these mp3 files it was
getting a Forbidden access message. The FLV just prevents the FLV player from
showing up at all (not even the skin).

Can anyone figure out why, that it would work over all the other computers and
NOT the one? On that person's computer, we tried it in IE, Firefox, even Chrome
and the application doesn't load. We even cleared the cache, did a hard refresh
and still nothing.

However, the other computers work just fine.


ALL the computers have the latest Flash software installed.

What could cause this problem?