The size of the files which can be sorted or merged by MFJSORT(EXTSM) is determined by the record length, number of sort fields, sort field lengths, the amount of memory available, and the amount
of disk space available for virtual paging.
Resolution:
Make additional real or virtual memory available, or reduce the file size or the number and length of sort/merge fields, and
retry the sort/merge operation. Contact Customer Care if the problem persists.