exceeded allowed depth

  Explanation:  Either a programming error  has  occurred  or  the
  resource  name  tree  does  not  have  enough  depth.   The lock
  management services allow a certain depth to the  resource  name
  tree.

  User Action:  This error message indicates a possible  error  in
  the    locking   protocols.    Contact   your   Oracle   support
  representative for assistance.