I just replaced all of the save instances of the CuteEditor in my test area to reference and pull XHTML. Using an instance, I selected and displayed an MP3, saved it in the database as XHTML, and it did not fix it - it still won't play. Properties for the embedded media player reference still shows...

C:\Program Files\Mozilla Firefox\.\uploads\media\1\jjonesassign1.mp3

...for FireFox, and the source for the page shows...

"/uploads/media/1/jjonesassign1.mp3" 

(quotes are there, no help).