Invalid controller specified (what.php)

#0 /home/ca211/public_html/cms/library/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#1 /home/ca211/public_html/cms/library/Zend/Application/Bootstrap/Bootstrap.php(97): Zend_Controller_Front->dispatch()
#2 /home/ca211/public_html/cms/library/Zend/Application.php(366): Zend_Application_Bootstrap_Bootstrap->run()
#3 /home/ca211/public_html/cms/public/index.php(167): Zend_Application->run()
#4 {main}