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Have you made sure the domain part of the username is in capitals?
The user running the configuration console needs to be an Administrator in Management Reporter in order to import companies. Most likely you are logged in as the domain administrator, but either ugpraded a MR database where this user was not a MR user, or you created a new database and selected some other user as the MR Administrator. Please log onto this machine as the user you selected as the MR Administrator, and then you will be able to import companies.