When we login as administrator, click on Modules > Activities > Quiz and click on "Blocks editing on/off" button, then an error message "A required parameter (module) was missing" will be displayed.

Also please have a look at url "http://demo.moodle.org/admin/module.php?module=quiz" and when we click on "Blocks editing on/off" button then url "http://demo.moodle.org/admin/module.php?adminedit=on&section=modsettingquiz" will display "A required parameter (module) was missing". Please have a look at attached documents also. As a result, the edit mode of quiz settings will not be displayed.

It would be great if you reply this mail ASAP.