have you ever tried form_error() ?

[eluser]pistolPete[/eluser]
There is no difference between using arrays and multiple calling set_rules().
The cascading rules example from the userguide using arrays would look like:

Code:

$config = array(
               array(
                     'field'   => 'username',
                     'label'   => 'Username',
                     'rules'   => 'required|min_length[5]|max_length[12]'
                  ),
               array(
                     'field'   => 'password',
                     'label'   => 'Password',
                     'rules'   => 'required|matches[passconf]'
                  ),
               array(
                     'field'   => 'passconf',
                     'label'   => 'Password Confirmation',
                     'rules'   => 'required'
                  ),  
               array(
                     'field'   => 'email',
                     'label'   => 'Email',
                     'rules'   => 'required|valid_email'
                  )
            );