Fatal error on Authentication.php

[Butters]

Hi,

I have a serious problem,users can't login or register,
when registering this error appears:
Fatal error: Call to undefined method Validate::isdni() in /home/goldphar/public_html/authentication.php on line 50

this is line 50 in /public_html/authentication.php:

    <form action="{$base_dir_ssl}authentication.php" method="post" id="login_form" class="std">

Help please.

[rocky]

It seems that your authentication.php and classes/Validate.php are from different versions of PrestaShop. Make sure that the function isDni($dni) exists in classes/Validate.php.