Another piece of info...
I discovered the raw .swf functions properly when played via the standalone Flash player (188.8.131.52). It's only when embedded in a webpage that it won't function (in any browser, as mentioned in original post). I use Dreamweaver to embed the .swf, so the HTML coding must be correct...
Could you please open a new bug report on this over at bugbase.adobe.com? We'll need steps to reproduce and a link to your site (or code/.swf) If you'd like to keep anything private, please feel free to email me at firstname.lastname@example.org with your bug number and forum url and I'll add the attachments for internal use only.
Finally, please post back with the URL so that others affected can add their comments and votes.