could not edit identity.php and header.php

[elaine]

i opened the files identity.php and it says:

identity.php
PHP script text
<?php
/*
* 2007-2011 PrestaShop
*
* NOTICE OF LICENSE
*
* This source file is subject to the Open Software License (OSL 3.0)
* that is bundled with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://opensource.org/licenses/osl-3.0.php
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to [email protected] so we can send you a copy immediately.
*
* DISCLAIMER
*
* Do not edit or add to this file if you wish to upgrade PrestaShop to newer
* versions in the future. If you wish to customize PrestaShop for your
* needs please refer to http://www.prestashop.com for more information.
*
* @author PrestaShop SA
* @copyright 2007-2011 PrestaShop SA
* @version Release: $Revision: 1.4 $
* @license http://opensource.org/licenses/osl-3.0.php Open Software License (OSL 3.0)
* International Registered Trademark & Property of PrestaShop SA
*/

require(dirname(__FILE__).'/config/config.inc.php');
ControllerFactory::getController('IdentityController')->run();

what does it mean?

the same thing happens with header.php

<?php
/*
* 2007-2011 PrestaShop
*
* NOTICE OF LICENSE
*
* This source file is subject to the Open Software License (OSL 3.0)
* that is bundled with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://opensource.org/licenses/osl-3.0.php
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to [email protected] so we can send you a copy immediately.
*
* DISCLAIMER
*
* Do not edit or add to this file if you wish to upgrade PrestaShop to newer
* versions in the future. If you wish to customize PrestaShop for your
* needs please refer to http://www.prestashop.com for more information.
*
* @author PrestaShop SA
* @copyright 2007-2011 PrestaShop SA
* @version Release: $Revision: 1.4 $
* @license http://opensource.org/licenses/osl-3.0.php Open Software License (OSL 3.0)
* International Registered Trademark & Property of PrestaShop SA
*/

$controller = new FrontController();
$controller->displayHeader();

why couldn't i open it?
thanks for the help.