illegal target for assignment

  Explanation:    Oracle   Rdb   restricts   the    targets    for
  BLR$K_ASSIGNMENT  to  be  columns within the table referenced by
  the  BLR$K_STORE,  BLR$K_STORE2   or   BLR$K_PLACE   statements.
  Additionally,   built-in   functions,  such  as  BLR$K_GET_INFO,
  BLR$_CURRENT_TIME, BLR$_CURRENT_TIMESTAMP, and BLR$_CURRENT_DATE
  can only be sources in an assignment, not in targets.

  User Action:  If  you  called  Oracle  Rdb  using  DSRI,  please
  correct  the  query  string.   Otherwise,  contact  your  Oracle
  support representative for assistance.  You will need to provide
  the statements that produced this error.