Flash mp3 player does not display

I use a Flash mp3 player in some of my blogs which works fine in IE7 and Safari. It used to work in Firefox, but as of Firefox 3.0.3 it stopped working. The Flash player works in a regular html page in this version of Firefox, so that suggests WordPress is the problem.

Related question: Someone else installed WordPress for me, so I don’t really know which version I’m using. I poked around on all of the admin tabs but wasn’t able to find a version number.