ECC Run Data Load logfile shows "Routine OutFile cannot write to a file."

Some ECC FULL_LOAD runs show this in the logfile:

     JOB Details: <-- END --->

      Please check the output Log of Concurrent program for error details

      Error Details: <-- START --->

      Error Details: <-- END --->

     Routine OutFile cannot write to a file.

     Check that you have privileges to create and write to files in the file's directory. Contact your system administrator to obtain create and write privileges.

     Check that there is sufficient disk space on your system to create a file. Contact your system administrator to obtain more disk space.

The load completes normally along with child workers

There is plenty of diskspace on both  $ECC_LOG_DIR and $APPLCSF on the EBS side.