"invalid format parameter"
*Cause: The format parameter passed to a UTL_PG conversion routine
was invalid. The format parameter should have been built by
a prior call to either MAKE_RAW_TO_NUMBER_FORMAT or
*Action: Check to be sure that the format parameter was built by
MAKE_RAW_TO_NUMBER_FORMAT or MAKE_NUMBER_TO_RAW_FORMAT,
and that it was not accidentally overwritten or modified
by the PL/SQL procedure.