dmd54 on "button ain't working"

Here is the sendmail php

<?php
  		if(isset($_POST['submit'])) {
          error_reporting(E_NOTICE);
          function valid_email($str)
          {
          return ( ! preg_match("/^([a-z0-9\+_\-]+)(\.[a-z0-9\+_\-]+)*@([a-z0-9\-]+\.)+[a-z]{2,6}$/ix", $str)) ? FALSE : TRUE;
		     }
          if($_POST['name']!='' && $_POST['email']!='' && valid_email($_POST['email'])==TRUE && strlen($_POST['comment'])>1)
          {
              $to = preg_replace("([\r\n])", "", hexstr($_POST['receiver']));
			  $from = preg_replace("([\r\n])", "", $_POST['email']);
			  $subject = "Website contact message from ".$_POST['name'];
              $message = $_POST['comment'];

			  $match = "/(bcc:|cc:|content\-type:)/i";
				if (preg_match($match, $to) ||
					preg_match($match, $from) ||
					preg_match($match, $message)) {
				  die("Header injection detected.");
				}
              $headers = "From: ".$from."\r\n";
   			  $headers .= "Reply-to: ".$from."\r\n";

        if(mail($to, $subject, $message, $headers))
              {
                  echo 1; //SUCCESS
              }
              else {
                  echo 2; //FAILURE - server failure
              }
          }
          else {
       	  echo 3; //FAILURE - not valid email

          }
		  }else{
			 die("Direct access not allowed!");
		   }

		    function hexstr($hexstr) {
				  $hexstr = str_replace(' ', '', $hexstr);
				  $hexstr = str_replace('\x', '', $hexstr);
				  $retstr = pack('H*', $hexstr);
				  return $retstr;
				}

      ?>