a problem with superfish (solved)

hello,
i installed superfish according to the http://drupal.org/node/436336 , and it has worked, but there's a bug as you can see at http://www.hk-pk.com/

well, the codes i'm using are as follows:

<div id="superfish"><?php
$tree = menu_tree_page_data('secondary-links');

  $output = '';
  $items = array();

  // Pull out just the menu items we are going to render so that we
  // get an accurate count for the first/last classes.
  foreach ($tree as $data) {
    if (!$data['link']['hidden']) {
      $items[] = $data;
    }
  }

  $num_items = count($items);
  foreach ($items as $i => $data) {
    $extra_class = NULL;
    if ($i == 0) {
      $extra_class = 'first';
    }
    if ($i == $num_items - 1) {
      $extra_class = 'last';
    }
    $link = theme('menu_item_link', $data['link']);
    if ($data['below']) {
      $output .= theme('menu_item', $link, $data['link']['has_children'], menu_tree_output($data['below']), $data['link']['in_active_trail'], $extra_class);
    }
    else {
      $output .= theme('menu_item', $link, $data['link']['has_children'], '', $data['link']['in_active_trail'], $extra_class);
    }
  }

print $output;
?></div>

thx.