I installed the SEO URL Beta 3.0 ver. and after I finished the instruction I went to the config in the admin and got the following error at the top of the page

Fatal error: Class coreadvancedsearchresultseourlplugin: Cannot inherit from undefined class coreadvancedsearchseourlplugin in /home/biafpgb/public_html/includes/classes/seo/seo.url_plugins/__core__/advanced_search_result.php on line 14
what does mean and how do I fix it