Of course without seeing and testing the page, it's impossible to tell for sure whats wrong. Can you post a link to the actual page.
That being said, my first guess is that it's being published with something like this in the <object> code:
swfversion 11.0.0.0
... meaning that some version of Flash player 11 is required to play the .swf. For viewers with that version installed it works, for those without, it doesn't.This has been a real common problem when "Publish" sticks that version 11 requirement in the code.
So open the HTML page. find that part of the <object> code and edit the code to read swfversion 10 instead.
Use DreamWeaver or NotePad or whatever to edit... but without seeing the page, that's my best guess.
Best wishes,
Adninjastrator
