Error con PHPMailer

[mblascog]

Buenas, siguiendo con el tema, que aún no he solucionado.
He bajado la última versión, de la página de Github, de class.phpmailer.php (5.2.9), de class.smtp.php, y PHPMailerAutoload.php que hasta ahora nunca había utilizado.

Y en la página php he substituido:
- require(""class/class.phpmailer.php")
por
- require ("class/PHPMailerAutoload.php");

Y fatal, al ejecutar la página sale este error:

Código texto:

* @author Jim Jagielski (jimjag) 
 * @author Andy Prevost (codeworxtech) 
 * @author Brent R. Matzelle (original founder)
 * @copyright 2012 - 2014 Marcus Bointon
 * @copyright 2010 - 2012 Jim Jagielski
 * @copyright 2004 - 2009 Andy Prevost
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @note 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.
 */

/**
 * PHPMailer SPL autoloader.
 * @param string $classname The name of the class to load
 */
function PHPMailerAutoload($classname)
{
 //Can't use __DIR__ as it's only in PHP 5.3+
 $filename = dirname(__FILE__).DIRECTORY_SEPARATOR.'class.'.strtolower($classname).'.php';
 if (is_readable($filename)) {
 require $filename;
 }
}

if (version_compare(PHP_VERSION, '5.1.2', '>=')) {
 //SPL autoloading was introduced in PHP 5.1.2
 if (version_compare(PHP_VERSION, '5.3.0', '>=')) {
 spl_autoload_register('PHPMailerAutoload', true, true);
 } else {
 spl_autoload_register('PHPMailerAutoload');
 }
} else {
 /**
 * Fall back to traditional autoload for old PHP versions
 * @param string $classname The name of the class to load
 */
 function __autoload($classname)
 {
 PHPMailerAutoload($classname);
 }
}
?>
Fatal error: Class 'PHPMailer' not found in prueba.php on line 5
 

La línea 5 es $mail = new PHPMailer();

El código que he descargado, PHPMailerAutoload.php es el siguiente:

Código PHP:

<?php
/**
 * PHPMailer SPL autoloader.
 * PHP Version 5
 * @package PHPMailer
 * @link https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
 * @author Marcus Bointon (Synchro/coolbru) <[email protected]>
 * @author Jim Jagielski (jimjag) <[email protected]>
 * @author Andy Prevost (codeworxtech) <[email protected]>
 * @author Brent R. Matzelle (original founder)
 * @copyright 2012 - 2014 Marcus Bointon
 * @copyright 2010 - 2012 Jim Jagielski
 * @copyright 2004 - 2009 Andy Prevost
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @note 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.
 */
 
/**
 * PHPMailer SPL autoloader.
 * @param string $classname The name of the class to load
 */
function PHPMailerAutoload($classname)
{
    //Can't use __DIR__ as it's only in PHP 5.3+
    $filename = dirname(__FILE__).DIRECTORY_SEPARATOR.'class.'.strtolower($classname).'.php';
    if (is_readable($filename)) {
        require $filename;
    }
}
 
if (version_compare(PHP_VERSION, '5.1.2', '>=')) {
    //SPL autoloading was introduced in PHP 5.1.2
    if (version_compare(PHP_VERSION, '5.3.0', '>=')) {
        spl_autoload_register('PHPMailerAutoload', true, true);
    } else {
        spl_autoload_register('PHPMailerAutoload');
    }
} else {
    /**
     * Fall back to traditional autoload for old PHP versions
     * @param string $classname The name of the class to load
     */
    function __autoload($classname)
    {
        PHPMailerAutoload($classname);
    }
}
?>
 

Muchas gracias