CodeIgniter appears to have a BUG.

You don't have an else. Therefor it always run, even thought your validation failed.

PHP Code:

public function index()
{
    $error = 0;
    $realname = "";
    $username = "";
    $word = "";

    $this->load->helper(array('form', 'url','file'));
    $this->load->library('form_validation');

    $config = array(
        array('field' => 'rname', 'label' => 'RealName', 'rules' => 'required', 'errors' => array( 'required' => 'Provide%s')),
        array('field' => 'uname', 'label' => 'Username', 'rules' => 'required', 'errors' => array( 'required' => 'Provide%s')),
        array('field' => 'word', 'label' => 'Word', 'rules' => 'required', 'errors' => array( 'required' => 'Provide%s'))
    );

    $this->form_validation->set_rules($config);
    if ($this->form_validation->run() == FALSE)
    {
        $this->load->view('names');
    }
    else
    {
        $realname = $this->input->post('rname');
        $username = $this->input->post('uname');
        $word = $this->input->post('word');

        if(!file_exists("C:xampp/htdocs/file1/$realname")) exit ("$realname DoesNotExist");
        if(!file_exists("C:xampp/htdocs/file2/$realname/$username")) exit ("$username DoesNotExist");
        if(!file_exists("C:xampp/htdocs/file3/$realname/$word")) exit ("$word DoesNotExist");

        if(isset($_POST['submit'])) redirect(BASE_URL.'home');
    }
}