Datacom DBUTILITY backup job receives DB00501E - OPEN ERROR - RETURN CODE 56 (001).
RC 56 (001) means that a customized module called DBMSTLST that is loaded from the CUSLIB loadlib was not the correct one for the version of the Datacom software that was run in the STEPLIB.
To resolve this, be sure that you have only one DBMSTLST in the job, and that its version matches the version of the base software (either CAAXLOAD or CABDLOAD) used in this job.
As always, please contact Broadcom support for CA Datacom if you have further questions.