CentOS GUI problem using Gnome

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http://unix.stackexchange.com – For some reason lately when I try to set the date using the interface, or simply install a .rpm by double clicking the dialog that should prompt me to input my passowrd just shakes like it has a bug. The dialog window that shakes has the title "Authenticate" Privileges are required to change the system time/install software/etc Ann application is attempting to perform an action that requires privileges. Authentication as the super user is required to perform this action Authenticat Failure And i have to options: Cancel and Authenticate. The problem is this windows just shakes and dissapears (HowTos)