Fast Load abend - IEC146I 513-04

You are running Platinum Fast Load job and the job fails on you with an "IEC146I 513-04" error.

IEC146I 513-04 means
"An OPEN macro instruction was issued for a magnetic tape data set allocated to a device that already has an open data set on it. Make sure that the first data set is closed before the second is opened, or allocate the second data set to a different device. This error may be due to a
previous abnormal end associated with the same unit in the same step. If so, correct the error causing the previous abnormal end."

Problem:
As per the above message, you are trying open the dataset for two different purposes in the same job step.

In your LOAD card, see what you've specified for INDDN. In my case, I had specified INDDN SYSREC.

Fast Load user guide says "If you will be performing an OUTPUT-CONTROL ALL type load, and you want to specify INDDN SYSREC, you must also specify UNLDDN and change its default value. Otherwise, Unicenter Fast Load will try to use SYSREC as an input and a work file."

OUTPUT-CONTROL ALL is the default. I noticed that I didn't have a UNLDDN DD name in my JCL.

Fix:
Either specify a UNLDDN DD in your JCL step or change INDDN to something other than SYSREC. I changed it to SYSULD and it worked.