Customers can't log in at front office Prestashop 1.4.6.2

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Problems :
Customer cant login to your prestashop website.

Solutions :
In your module/statsdata/statsdata.php file, please comment out the following line (should be around line 189):
$params['cookie']->id_guest = $guest->id;
 For some users, there to be a conflict between PHP cookies and redirection, and this change has been found to help resolve it in those situations.