FUNL0020 (ddname) already enqueued exclusive by (jobname stepname).
The input database file is being updated by a Model 204 job and hence cannot be enqueued in exclusive mode by Fast/Unload.load. Either wait until the updating job is completed or use the NOENQ Fast/Unload parameter to process the file without any enqueueing. Note that the latter option could result in errors in the unload phase of Fast/Unload.