Hi,

To solve this problem, please go to the file app\code\local\Sns\Producttabs\Model\System\Config\Source\OrderBy.php, find and replace the code bellow :

array('value' => 'best_sales',	'label' => Mage::helper('producttabs')->__('Best Sales')),
array('value' => 'created_at', 	'label' => Mage::helper('producttabs')->__('New Products')),

BY:

array('value' => 'created_at', 	'label' => Mage::helper('producttabs')->__('New Products')),
array('value' => 'best_sales',	'label' => Mage::helper('producttabs')->__('Best Sales')),

Thanks,