Missing Model

No class found for the model AddressBook

Notice: this error is being rendered by the app/views/errors/missing_model.thtml view file, a user-customizable error page.

Fatal: Unable to load model AddressBook

Fatal: Create Class:

<?php
class AddressBook extends AppModel
{
    var $name = 'AddressBook';
}
?>

in file : app/models/address_book.php

Fatal error: Call to a member function css() on a non-object in /var/www/vhosts/commentart.com/httpdocs/app/views/layouts/default.thtml on line 44