Well! I thought I was answering the question. My reference to the 'Manage Users' dialog is a reference to functionality within AdminStudio. If you use this dialog, then you will be able to assign permissions to use the Application Catalog.
For the Administrator role, SQL Server will be configured with the server roles of DB CREATOR and SECURITY ADMIN and the database role of DB OWNER. For the Author role, SQL Server will be configured with the database role of DB DATAREADER , DB DDLADMIN, and DB DATAWRITER. Once these roles are defined, the same 'Manage Users' dialog will allow you to enable specific privledges within the AdminStudio tools for the various users. These privledges are stored in the various assys - prefixed tables in the Application Catalog.
It is recommended that you use this dialog to configure all of your user permissions. Later, you can use Enterprise Manager to restrict the server permissions on a user-by-user basis.
Allen Saxton