Did you load the swf file to your server?
If you have done that, in DW click on the table or div that you have embedded your swf in ( properties panel) and make sure the file property reads the exact location of your swf on your server.
i.e <object>
<param name="movie" value="http://www.yourserver.com/yourimages/your_movie.swf" />
<param name="quality" value="high" />
</object>
Hope this helps.