Hubs can be completely customized to allow or disallow certain actions. It may be that your hub administrator has disabled the particular feature you are trying to access.
You can contact your hub administrator to find out if the permission can be changed.
Your Hub administrators contact information can be found by going to:
My Hubs > Select the Hub from the Drop Down > Click People on the left-hand side > Click the Name link under the Hub Administrators section the bottom right.
You will then be taken to their profile page which will show you their contact information.