The Universal Email code uses an if statement to evaluate if the post came from the same page and same server, this must not be working correctly when you access the page at www.sitename.com
You can try changing:
if ((($_SERVER["REQUEST_METHOD"] == "POST") && (isset($_SERVER["HTTP_REFERER"]) && strpos(urldecode($_SERVER["HTTP_REFERER"]), urldecode($_SERVER["SERVER_NAME"].$_SERVER["PHP_SELF"])) > 0) && isset($_POST))) {
to:
if ($_SERVER["REQUEST_METHOD"] == "POST") {