Bug: Error when AJAX request encounters the redirect function

function redirect($location, $method = FALSE)
{
    $location = str_replace('&', '&', $this->insert_action_ids($location));

    if (count($this->EE->session->flashdata))
    {            
        // Ajax requests don't redirect - serve the flashdata

        if ($this->EE->input->is_ajax_request())
        {
            // We want the data that would be available for the next request
            $this->EE->session->_age_flashdata();

            $this->EE->load->libarary('javascript');

                die($this->EE->javascript->generate_json(
                            $this->EE->session->flashdata));
        }
    }

    if ($method === FALSE)
    {
        $method = $this->EE->config->item('redirect_method');
    }        

    switch($method)
    {
        case 'refresh'    : header("Refresh: 0;url=$location");
            break;
        default            : header("Location: $location");
            break;
    }

    exit;
}