Here are the first 25 lines from /includes/classes/class.phpmailer.php from the Zen Cart v1.5.3 codebase:
Code:
<?php
/*~ class.phpmailer.php
.---------------------------------------------------------------------------.
| Software: PHPMailer - PHP email class |
| Version: 5.2.6 |
| Site: https://github.com/PHPMailer/PHPMailer/ |
| ------------------------------------------------------------------------- |
| Admins: Marcus Bointon |
| Admins: Jim Jagielski |
| Authors: Andy Prevost (codeworxtech) [email protected] |
| : Marcus Bointon (coolbru) [email protected] |
| : Jim Jagielski (jimjag) jimjag###################### |
| Founder: Brent R. Matzelle (original founder) |
| Copyright (c) 2010-2012, Jim Jagielski. All Rights Reserved. |
| Copyright (c) 2004-2009, Andy Prevost. All Rights Reserved. |
| Copyright (c) 2001-2003, Brent R. Matzelle |
| ------------------------------------------------------------------------- |
| License: Distributed under the Lesser General Public License (LGPL) |
| http://www.gnu.org/copyleft/lesser.html |
| This program is distributed in the hope that it will be useful - WITHOUT |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. |
'---------------------------------------------------------------------------'
*/
Obviously, the code that you have for that class file isn't the version supplied with Zen Cart v1.5.3.