This is the correct HTML code for embedding Flash. It validates 100%.
Code:
<object type="application/x-shockwave-flash" data="filename.swf"
width="200" height="200"
id="movie1">
<param name="movie" value="filename.swf">
<p>You need the Flash plugin.</p>
<p<a href="http://www.macromedia.com/go/getflashplayer/">Download Macromedia Flash Player</a></p>
</object>
John