Display extra information adjacent to system_settings_form() output
I think this must be

// ...inside drupal_get_form callback
// $form has some form elements in it

if (!hay_problemas()){
  $form['warning'] = array(
    '#attributes' =&gt; array('class' =&gt; array('warning')),
    '#markup' =&gt; t('WARNING:  Filesystem permission are broken'),
    '#weight' =&gt; -10, //set position relative to other $form['key']
  );
}

return system_settings_form($form);