Starting Download Problem with IIS 6

[xeroxero]

I am attempting to make a small popup window push a downloaded file.
What works fine with the Visual Studio 2005 web server does not appear
to work with IIS6.

My main page code looks like this:

LiteralControl litMove = new LiteralControl( );
litMove.Text = @"
<script language='JavaS cript'>
<!--
var dlWindow = window.open('th eFile', 'fileDl',
'toolbar=1,loca tion=0,director ies=0,status=0, menubar=0,scrol lbars=0,resizab le=0,width=10,l eft=10,height=2 4');
//-->
</script>
";
litMove.Text = litMove.Text.Re place( "theFile" , theFile );
this.pageBody.C ontrols.Add( litMove );

The actual download code (in a new page appearing as "theFile" in the
previous code page above) looks like this:

Response.Clear( );
Response.AddHea der( "Content-Disposition" , "attachment;fil ename=" +
HttpUtility.Url PathEncode(myFi le) );
Response.AddHea der( "Content-Length" , new FileInfo( fullFilePath
).Length.ToStri ng() );
Response.Conten tType = "applicatio n/octet-stream";
Response.Transm itFile( fullFilePath );
Response.End();

What happens is that on IIS6, the popup appears for 1/2-second and
disappears. On the Visual Studio Cassini server, the window appears
and then the user is prompted for save.

Users are IE7 clients.

Thanks.