try 'unhiding' the page with the repository module on it and see if that works.  I understand you only want administrator to upload, but if you hide the page, then no one can see the items.  By default, only administrators can upload anyway, so you do not have to do anything special to acheive your goal. Look at the repository module settings page,  you'll see a series of roles, one of which is 'Upload Roles'. You can check off what roles are required to upload an item.