transaction BLR is nested too deeply

  Explanation:   BLRK_TRANSACTION  can  not  be  nested  within  a
  BLR$K_FOR  or  a BLR$K_STATEMENT.  You can not start, commit, or
  rollback a transaction from within these statements.

  User Action:  This is an unexpected internal error.  If you  are
  using  DSRI,  then  please  recode the DSRI request to avoid the
  nesting.  If you are using  SQL,  contact  your  Oracle  support
  representative  for  assistance.   You  will need to provide the
  statements that produced this error.