this error does seem to suggest the domino server is not part of the Notes domain that it is expecting.
if you're sure you've imported from this server previously, then perhaps a re-run of the permissionsWizard can shed some light.
if there is an access or authenitcation issue, this would surely show it in the results.
i'm not hip with the notes domain and its configuration but perhaps a double check with that piece would show something.