I have faced this error while initiating data loads in PFC monitor of DSiM.
It has the same number assigned as another step of a process that belongs to the same data delivery agreement or the same process definition. The other step has the status Error or On Hold, therefore, this step is blocked from further processing.
Option #1 : You need to cancel the process which is showing status with "Ërror or on hold" and click on refresh it will re-iniate data load process. Please find attached for details
Option # 2 :
Go to the Process Monitor UI and locate the step that has the status Error From. Log on to SAP NetWeaver Business Warehouse and go to transaction Data Warehousing: Modeling (RSPC). Select the erroneous process chain and correct the error. Go to the Process Monitor UI and restart the step.