rss symbol causes fatal-error on click on it

hi,

when i click on an rss symbol, i get this error message:

Fatal error: Cannot use object of type stdClass as array in /var/www/drupal6/modules/node/node.module on line 1688

the code lines of the node.module are:

foreach ($extra as $element) {
      if (isset($element['namespace'])) {
        $namespaces = array_merge($namespaces, $element['namespace']);
      }
    }

any ideas?