BO: internal 500 error on editing SEO 1.5.4.1

[r2get]

Upgraded from 1.5.2 to 1.5.4 and then 1.5.4.1 > from 152 to 154 manual to 1541 1 click module

Everything works ok but in the backoffice going to SEO Prefrences URL's it shows all items but when i want to edit it gives a internal server error 500. With dev mode on the error is:

Fatal error: Uncaught exception 'ReflectionException' with message 'Class CategoryController_bck does not exist' in /home/XXXXX.com/public_html/classes/Meta.php:71 Stack trace: #0 /home/XXXXX.com/public_html/classes/Meta.php(71): ReflectionClass->__construct('CategoryControl...') #1 /home/XXXXX.com/public_html/controllers/admin/AdminMetaController.php(229): MetaCore::getPages(true, '404') #2 /home/XXXXX.com/public_html/classes/controller/AdminController.php(1430): AdminMetaControllerCore->renderForm() #3 /home/XXXXX.com/public_html/classes/controller/Controller.php(167): AdminControllerCore->initContent() #4 /home/XXXXX.com/public_html/classes/Dispatcher.php(349): ControllerCore->run() #5 /home/XXXXX.com.com/public_html/b-admin/index.php(50): DispatcherCore->dispatch() #6 {main} thrown in /home/XXXXX.com.com/public_html/classes/Meta.php on line 71

how can this be? (replaced site name to XXXXX.com for privacy)