[ForceHSS]

upgrade to 4.2.3 will fix it
or
As of vBulletin 4.2.2, notices and warnings are no longer suppressed by default like in previous versions of the software. This means that on some servers, you may see warnings that you never saw before. In order to stop them from showing, please add the following line to your config.php file under the <?php line:

PHP Code:

define('SKIP_DS_ERRORS', true);