If it is a local machine account go to My Computer >Manage >Local Users and Groups >Groups >QlikView Administrators and add the user account here. If it is on a domain the QlikView Administrators group will show up in your AD and the user(s) can be added here.
Hope this helps!
P.S. if you are adding the currently logged in user you will need to logoff and log back into your system in order to be able to access the QMC.