IE6 SP2 blocking dynamic file export

[Guest]

I have a web application that featues the ability to export data to excel.

The application opens in a popup window from the login page that detects if
the application's popup window is blocked and instructs the user to "Always
allow popups from this site". After the user has logged into the application,
they choose the excel export. The application opens a popup window to the
file export page. You hear the explorer "blip" that tells me that the file
attachment was blocked then the popup window closes.

This only happens in IE6SP2. Prior versions of IE, it prompted the user to
Open or Save. If they chose Open, it would properly open the file in excel.

Method Used in the file export page:

Response.Clear();
Response.Charset="";
Response.ContentType = "application/vnd.ms-excel";
Response.AddHeader("Content-Disposition", "attachment; "+
"filename=ClientTrackExport.xls");
//Write out excel file
Response.Flush();
Response.End();

How can I get this to work in IE6 SP2?