First, go to the user you want to give admin's Contributions page, then click "user rights management". Now click the checkboxes on the right (not right as of postions, i am talking about the right like powers.) you want to give. For me, i want all of those checkboxes checked. Please note that you do not have to have all checkboxes checked on admin rights for all the users you want to give admin rights, but please check all boxes on admin rights for me.