The parameter for the EXTDESC keyword is not valid; the keyword is ignored.
20
Cause . . . . . : The parameter for EXTDESC is not valid. The parameter for EXTDESC must be a literal representing a file name in one of the following forms: 'LIBRARY/FILE', '*LIBL/FILE', or 'FILE'. The file used for the external descriptions defaults to the file specified in position 7 of the File specification.