Yo lo que creo es que si quitaras esto te funcionaria:
<HTML>
<HEAD>
<TITLE>Email Form v1.1 - Powered by: (http://www.phpscriptcenter.com/emailform.php)</TITLE>
</HEAD>
<BODY BGCOLOR=#ffffff>
<!--
Powered by: Email Form Version 1.1 (
http://www.phpscriptcenter.com/emailform.php)
-->
O sea, empezar directamente por:
<?php