Hi,
you can do one thing.(so that you don't have to face the browser problem.)
When you get the result (eg: .zip file) you can load Popup Window like this.
step 1: Create Div based section in your web page
<div id="dialog" style="display:none">
<![CDATA[<%-- Add File Name with download link -- %>]]>
</div>
Step 2: Write JavaScript to show dialog in popup
function ShowDialog(isValidAddress) {
$("#dialog").fadeIn(300);
}
function HideDialog() {
$("#dialog").fadeOut(300);
}
step 3: Call javascript function showDialog from Code behind.
RegisterStarupScript();
Refer this link better idea
http://forum.jquery.com/topic/a-very-simple-popup-box-div[
^]
If this will help you then please accept this as answer and vote for this.
Thanks