I was guessing that what you were trying to do was create a link back to the previous page (the page that "referred" you to the current page).
$ENV{HTTP_REFERER} isn't reliable for this in general, due to some proxies and some older browsers. But it sounds from your original post as though you're using a CGI to create pages. So I'm unclear on what, exactly, you're trying to do. Are you trying to create a link back to the page from outside of your side that originally referred a session to your site? Or to some static page on your site?