I would avoid linked universes, they are cumbersome and won’t directly address your issue IMO.
The above error message will occur if you delete your universes, so don’t delete any universes until you have repointed your reports to use your new universe.
You should search for @BOUSER and read up on the “Manage Security” option under the tools menu in Designer… here is one such topic
dessa 
(BOB member since 2004-01-29)