vars = array

On my site, I found the string: $vars = array(); at the beginning of the function.
I have to disable this line for the forum post pages to use the Advanced Forum style.
Should I? Would it affect my site?

Michelle, I apologize for posting my question as a comment and not here. Thank you for the quick reply however it doesn't help, even when I move that line to the top of the function, the post page is using the default D5 theme.

function _phptemplate_variables($hook, $vars) {
  $vars = array();

  if (module_exists('advanced_forum')) {
    $vars = advanced_forum_addvars($hook, $vars);
  }

  if ($hook == 'page') {

    // These are the only important lines
    if (module_exists('page_title')) {
      $vars['head_title'] = page_title_page_get_title();
    }

  }
  return $vars;
}