Unable to Add/Edit User ( Administrators )

Upon Clicking on the Admin | Administrators Menu, clicking on user "admin", loads back to the main page ( System Status Dashboard ), upon inspecting the element the following was observed; <a href="config.php?display=&userdisplay=admin" id="ui-id-3" class="ui-corner-all" tabindex="-1" role="menuitem">admin</a> the display had a missing value. Also noticed, a warning: NOTE: Authorization Type is not set to 'database' in Advanced Setting - note that this module is not currently providing access control, and changing passwords here or adding users will have no effect unless Authorization Type is set to 'database', but when i checked the database (mysql) it was set to 'database'

to temporarily fix the problem, I added global $display, $amp_conf; at the start of the file.