ah. yeah since a SWF is considered active content and not an image...
not sure why you'd want to insert a SWF into a table with CSS. If you're just trying to arrange it, then add the SWF via the table HTML. if you ARE trying to set it as the background, i suppose you could always export your swf as an animated GIF which you should be able to apply to the table via CSS. you'll lose all interactivity though.