"Unable to load the requested class: form_validation"

[eluser]Bl4cKWid0w[/eluser]
I'm trying to use the form validation class, however, it doesn't seem to be working correctly. This is my code:

Code:

$this->load->helper('form');
           $this->load->library('form_validation');
      $this->form_validation->set_rules('clanName', 'Clan Name', 'required|callback_clanname_check|min_length[5]|max_length[50]');
      $this->form_validation->set_rules('clanMotto', 'Motto', 'required|min_length[5]|maxlength[250]');
      $this->form_validation->set_rules('clanEmail', 'Email', 'required|valid_email');
      
      if($this->form_validation->run() == FALSE){
        $this->load->view('ladders_join', $data);
      } else {
        $this->load->view('ladders_joined');
      }