Worpress 3.6.2. doesn´t work with qTranslate. The plugin is always disabled and the current version will not be accepted. There is the option to activate the plugin yet, but this will not work correctly.
There is a simple workaround. wp-content/plugins/qtranslate/qtranslate.php
die Zeile 90 wie folgt ändern:
define('QT_SUPPORTED_WP_VERSION', '3.6');