[Mark.B]

Edit your /includes/config.php file.

Change:

PHP Code:

$config['Database']['dbtype'] = 'mysql'; 


To:

PHP Code:

$config['Database']['dbtype'] = 'mysqli'; 


Also it'd be a good idea to do this while you're in there:
Add the following line to your /includes/config.php file, right under the <?php line:

PHP Code:

define('SKIP_DS_ERRORS', true);