Whenever A user tries to access an action not specified for him he gets
you are not authorized
I would like to show a custom message.
I would even like top replace this message
The system is unable to find the requested action "minzyz".
with a custom message
How Can I achieve that?
You should be able to set the message property of CAccessControlFilter: http://www.yiiframework.com/doc/api/1.1/CAccessControlFilter#message-detail in your controller. If that’s not enough and you need to throw some custom exceptions you could extend CAccessControlFilter, override the parts you want to change and use this one as your filterclass
Regarding customized errors in general: http://www.yiiframework.com/doc/guide/1.1/en/topics.error