Provo così, ma non funziona (cioè la popup non si chiude...):
codice:
<% 
IF Request.QueryString("referer") = "" THEN
  strReferer = Request.ServerVariables("HTTP_REFERER")%>
  <script language="javascript" type="text/javascript">
<!--
window.close();
//-->
</script>
<%
ELSE
  strReferer = Request.Querystring("referer")
END IF
%>