illegal string specification

  Explanation:  The service completed  successfully,  except  that
  the  character-position  parameters  specifying a substring of a
  string parameter were inconsistent because the ending  character
  position  is  less than the starting character position.  A null
  string is used for the substring.

  User Action:  The application program  should  verify  that  the
  starting  character  positions  are  less  than  or equal to the
  ending character positions.