If you try to access sitemap.php, you get a message stating "The sitemap is currently unavailable".
It appears there are some needed functions in functions/fwr_categories.php and functions/fwr_cat_functions.php. Enabling FWR Popout menu in admin - configuration - SEO URLs - SEO Pop Out Menu will allow the SiteMap to function correctly. If you don't want the pop out menu though, you don't get the sitemap either. Maybe they were intended to be a package deal?