You can temporarily force which enrolment plugins are enabled (those not specified will be disabled) in your config.php file. Edit config.php and add a sentence like this one, just before the line that reads equire_once(dirname(__FILE__) . '/lib/setup.php');:
$CFG->enrol_plugins_enabled = "manual";
This will temporarily enable the "manual" enrolment plugin, disabling the rest. Once you can log in, you can go to the enrolment plugins page. Before doing any changes there, and without loging out or letting the user session expire, remove the previous line from config.php. Now you can refresh the page to get the actual list of enabled plugins and disable the LDAP enrol one.
Hope that helps.
Saludos.
Iñaki.