I can confirm that there are errors appearing in firefox.
The cause seems to be the embedding method. There's a
conflict between the overlapping object and embed embedding methods
getFlashMovie function so that it correctly returns the reference
to the embedded swf for non-IE browsers. I don't know enough js to
let you know how to change that to fix it.
I would use SWFObject to fix this. It will just result in a
single embedding method and if that is the case then your existing
code works (I tested this by editing the html and just using
<embed> in firefox - instead of <object> wrapping the
<embed>). I recommend that you install Firefox with the
to understand this problem (and verify the solution) very quickly.