Popup windows - cross platform/browser

I have a popup script that uses flash and javascript. It seems to work fine on Safari, IE on a Mac, Firefox, but not on IE on a PC. Is there a code that I need to add, or a different approach I need to take?

here’s the flash code on a button for the popup:

on(press){
getURL(“javascript:MM_openBrWindow(‘photosite_main.html’,‘AVVA’,‘width=1024,height=662,left=200,top=200’)”);
}

heres the code in the html header:

<script language=“JavaScript”>
<!–
function MM_openBrWindow(theURL,winName,features) {window.open(theURL,winName,features);
}
//–>
</script>