title: custom config file not working with form validation
body: <p>i've set the validation rules in application/config/validation_rules.php and it looks like this 
  (short version)</p>
  
  <pre><code>$config = array(
          'member/register' =&gt; array(
              'field' =&gt; 'language',
              'label' =&gt; 'language',
              'rules' =&gt; 'required|min_length[5]|max_length[12]'
          ),
          array(
              'field' =&gt; 'email',
              'label' =&gt; 'email',
              'rules' =&gt; 'required|valid_email'
          ),
          array(
              'field' =&gt; 'password',
              'label' =&gt; 'password',
              'rules' =&gt; 'required|min_length[8]'
          ),
          array(
              'field' =&gt; 'verify_password',
              'label' =&gt; 'password',
              'rules' =&gt; 'required|min_length[8]|matches[password]'
          ));
  </code></pre>
  
  <p>and i'm calling it like this:</p>
  
  <pre><code>$this-&gt;config-&gt;load('validation_rules');
  $this-&gt;form_validation-&gt;set_rules($config);
  if($this-&gt;form_validation-&gt;run('member/register') == FALSE)
  {
      $page = array(
              'meta_title' =&gt; 'member registration',
              'load_page' =&gt; 'front/register_view'
      );
  
      $this-&gt;load-&gt;view('front/template', $page);
  }
  </code></pre>
  
  <p>not only is the validation_errors() function not showing anything but i'm also getting this error:</p>
  
  <pre><code>Message: Undefined variable: config
  </code></pre>
  
  <p>update: (here is my controller)</p>
  
  <pre><code>class register extends CI_Controller
  {
      function __construct()
      {
          parent::__construct();
          $this-&gt;load-&gt;library('form_validation');
      }
      function index()
      {
          $this-&gt;config-&gt;load('validation_rules', TRUE);
          $this-&gt;form_validation-&gt;set_rules($this-&gt;config-&gt;item('config', 'validation_rules'));
          if($this-&gt;form_validation-&gt;run('member/register') == FALSE)
          {
              //validation doesnt pass, load view
              $page = array(
              'meta_title' =&gt; 'member registration',
              'load_page' =&gt; 'front/register_view'
              );
  
              $this-&gt;load-&gt;view('front/template', $page);
          }
          else
          {
              $register_data = array(
              'language' =&gt; $this-&gt;input-&gt;post('language'),
              'email' =&gt; $this-&gt;input-&gt;post('email'),
              'password' =&gt; md5($this-&gt;input-&gt;post('password')),
              'fname' =&gt; $this-&gt;input-&gt;post('fname'),
              'lname' =&gt; $this-&gt;input-&gt;post('lname'),
              'phone' =&gt; $this-&gt;input-&gt;post('phone'),
              'address' =&gt; $this-&gt;input-&gt;post('address'),
              'address2' =&gt; $this-&gt;input-&gt;post('address2'),
              'city' =&gt; $this-&gt;input-&gt;post('city'),
              'state' =&gt; $this-&gt;input-&gt;post('state'),
              'zipcode' =&gt; $this-&gt;input-&gt;post('zipcode'),
              'gfname' =&gt; $this-&gt;input-&gt;post('gfname'),
              'glname' =&gt; $this-&gt;input-&gt;post('glname'),
              'gphone' =&gt; $this-&gt;input-&gt;post('gphone')
              );
              $this-&gt;session-&gt;set_userdata($register_data);
  
          }
      }
  
  
      function package()
      {
          $page = array(
          'meta_title' =&gt; 'Register Package',
          'load_page' =&gt; 'register_package_view'
          );
          $this-&gt;load-&gt;view('includes/template', $page);
      }
  
  
  
  
  }
  </code></pre>