Helaas nog niet gelukt.
Ik had de naam van de map veranderd van presta naar shop, daarna in phpMyAdmin de ps_shop_url veranderd maar kon niet meer in de backoffice van presta komen :-(
In de file settings.inc.php in de config directory staat geen '_PS_DIRECTORY_'
<?php
define('_DB_SERVER_', '');
define('_DB_TYPE_', 'MySQL');
define('_DB_NAME_', '');
define('_DB_USER_', '');
define('_DB_PASSWD_', '');
define('_DB_PREFIX_', 'ps_');
define('_MYSQL_ENGINE_', 'InnoDB');
define('_COOKIE_KEY_', 'mZvRFdgFI1rAWGKI4IR6NSqPAh9snzfCCOIYEsRbFI8FhTulYRQwOVwi');
define('_COOKIE_IV_', 'g22oNW41');
define('_PS_CREATION_DATE_', '2012-11-15');
define('_PS_VERSION_', '1.5.2.0');
define('_MEDIA_SERVER_1_', '');
define('_MEDIA_SERVER_2_', '');
define('_MEDIA_SERVER_3_', '');
?>