I am trying to implement the plugin above and able to allow Contributors access to the media library as well the Upload/Insert Images link in the text editor. When I click the "insert into post" button however, a dialogue box appears requesting login information. Any ideas why this might be happening? I try inputting the login credentials of the user I'm currently logged in as and the administrator credentials but unsuccessful. A broken image link appears in the post. Any help would be appreciated. Thanks in advance!