title: drupal_validate_form not validating more than one time on listing page
body: <p>i am using drupal_validate_form on a node listing page . 
  it is validating it correctly only for 1st item after that it is not checking validation.</p>
  
  <p>here is my code</p>
  
  <pre><code>     foreach($result as $r){
          $node_form = (object) array(
            'uid' =&gt; $user-&gt;uid,
            'type' =&gt; 'MY_CONTENT_TYPE',
            'language' =&gt; LANGUAGE_NONE,
          );
          $form = drupal_get_form('MY_CONTENT_TYPE_node_form',$node_form);
          $form['#submit'] = array('#type' =&gt; 'submit', '#value' =&gt; t('Next'));
  
          $old_fs = @unserialize($r-&gt;form_state);
          $old_fs['values']['uid'] = $user-&gt;uid;
          $node = (object) array(
            'uid' =&gt; $user-&gt;uid,
            'type' =&gt; 'MY_CONTENT_TYPE',
            'language' =&gt; LANGUAGE_NONE,
          );
          node_object_prepare($node);
          $form_state = array();
          $form_state['build_info']['args'] = array($node);
          $form_state['values'] = $old_fs['values'];
          $form_state['values']['op'] = t('Save');
          $form_state['submitted'] = 1;
          $form_state['complete form'] = array();
          $form_state['triggering_element'] = array('#parents'=&gt;array('next'),'#button_type'=&gt;'submit');
          unset($form['#token']);
          drupal_validate_form('MY_CONTENT_TYPE_node_form', $form, $form_state);
          $errors = form_get_errors();
          $noOfError = 'empty';
          if (!empty($errors)) {
            $noOfError = count($errors);
          } 
          form_clear_error();
      }
  </code></pre>
  
  <p>thank You in advance</p>