[] operator not supported for strings in ../includes/common.inc on line 2442

function l($text, $path, array $options = array()) {
  global $language_url;
  static $use_theme = NULL;

  // Merge in defaults.
  $options += array(
    'attributes' => array(),
    'html' => FALSE,
  );

  // Append active class.
  if (($path == $_GET['q'] || ($path == '<front>' && drupal_is_front_page())) &&
      (empty($options['language']) || $options['language']->language == $language_url->language)) {
    $options['attributes']['class'][] = 'active';
  }

'class' should be declared as an array() first.