[webizen]

You can use 5.2.x patch for php 5.2.16 (as stated in very end of the page http://choon.net/php-mail-header.php as below)

OR instead of waiting for me to roll out the patch according to the new version, you can try 5.2.x for 5.2 series and 5.3.x for 5.3 series.