If the web page displays the Flash video when the web page is opened, then unless you have another page that you want opened, the web page is opened.
If you only goal is to switch from that page to the index page after 40 seconds, then you can do that in the web page code rather than editing the Flash file. Just add the following code into the head section of the video's web page...
Thank you so much.
You have been of great help!