Error: Invalid controller specified (libs)

exception 'Zend_Controller_Dispatcher_Exception' with message 'Invalid controller specified (libs)' in /var/www/etc/library/Zend/Controller/Dispatcher/Standard.php:248
Stack trace:
#0 /var/www/etc/library/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#1 /var/www/etc/library/Zend/Application/Bootstrap/Bootstrap.php(97): Zend_Controller_Front->dispatch()
#2 /var/www/etc/library/Zend/Application.php(366): Zend_Application_Bootstrap_Bootstrap->run()
#3 /var/www/www/index.php(18): Zend_Application->run()
#4 {main}