"One-page"...sorry, that's short-hand for the Auctiva one-page lister, which you use when you edit a Saved listing.
I know there are several methods and stock code sets around for the Adobe Flash Player. My other question on the location of the movie/flash you are trying to play is important, as Auctiva and ebay won't host it. If the redirect to the URL is correct, I assume you could display it correctly with PREVIEW from Auctiva, but that's a best guess (I haven't tried what you're trying
).
If you do a PREVIEW and on that window/screen do a Right Mouse Click and select "View Source", you should be able to verify the embedded code is present and intact. I'm suspicious that it isn't working for other than the code being there.
Do you have a HTML editor like Frontpage you could use to copy the code from Auctiva and paste to its editor? That way you could use its PREVIEW to verify as a second check and make any "tweaks" to fix bugs.
Danno