Admin assignments are on an individual module basis. You may have been assigned as an Admin in one event and one Portal, for example, but not in other events or Portals. If you are a primary Admin, then you’ll have Admin access to the Profiles module, and can then grant global Admin access to any user, which allows that user to have Admin access to every module in the site. To do this, open the user’s Profile document, and then click the Add as Global Admin link in the right-hand panel.