In case that doesn't work, I would suggest explicitly specifying the mysql socket location in the config.inc.php. For example, the mysql socket could very well be /tmp/mysql.sock, so you would just find the line in config.inc.php that says:
$cfg['Servers'][$i]['socket'] = '';
and change it to say:
$cfg['Servers'][$i]['socket'] = '/tmp/mysql.sock';
That is what I think the error message is complaining about.