
If you have problems with internal links when parse seo links plugin in other component (outside content):

In seolinks content plugin, in start of function onPrepareContent (Joomla 1.5) 
or onContentBeforeDisplay (Joomla 1.6) paste:
 

if(!class_exists('ContentHelperRoute'))
 require_once(JPATH_SITE.DS.'components'.DS.'com_content'.DS.'helpers'.DS.'route.php');