There is no more space for more ACE entries.

  Explanation:  The space allocated in the root for  RMU's  access
  control  list  is full and cannot be extended either because the
  database is a single-file database or because  the  database  is
  open for other users.

  User Action:  If the database is a multi-file database,  execute
  the command when the database is not open.  If the database is a
  single-file database, then the  only  possible  changes  are  to
  delete existing access control entries and then add new ones.