Fields Data Validations

Change validations errors messages http://book.cakephp.org/view/125/data-validation

$validate = array( 
  'fieldname' => array( 
      'allowEmpty' => false,
      'required' => true,  
      'rule' => '/^.{6,40}$/', 
      'message' => 'Your message if rule failed', 
      ) 
);

List of built-in validation functions: http://api.cakephp.org/class_validation.html