Experienced an issue with a new App-V 5.1 install that is apparently known, but undocumented. After modifying the scripts and completing the install, I was unable to access the management interface. The error displayed was as follows: "You do not have access to this information. Please check your credentials." After querying the dbo.RoleAssignments table, I saw that the correct ADMIN groups and accounts were present. The additional step required to resolve the issue was to add the APP-V Management Server(s) machine account(s) (typically DOMAIN\MACHINENAME$) for the Network Service below and give it Appv_db_executor, db_datareader and db_datawriter. Once that was in place the console worked immediately.