NDMP User OK on vFiler not OK on same controller?

Hi

Creating a non-root NDMP user on a NetApp vFiler is fine and works perfectly but when a non-root NDMP user is set-up in the same group and other stuff on the controller that contains the vFiler it does like it.  NBU gives a "Unable to validate the filer wide credentials.  NDMP failed to verify host (58)".   We tried three different NetApp controllers, with usable vFiler NDMP accounts, and get the same message.   

Any ideas?

The basic idea is to get rid of all the separate vFiler logons because they are irrelevant when you can backup everything at the controller level. A vFiler path is the same as the controller path.