Just edit psmerchantassistant.php and replace line 743 by:
if (version_compare(_PS_VERSION_, '1.7.1', '>=')) {
$this->html .= $this->display(__FILE__, 'settings.tpl');
} else {
$this->html .= $this->display(__FILE__, 'views/templates/hook/settings.tpl');
}
1717157993
Just edit...