Unexpected Exception: Invalid controller specified (main)

#0 /var/www/ghlLib/Zend/Controller/Front.php(914): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#1 /var/www/html/index.php(31): Zend_Controller_Front->dispatch()
#2 {main}