SAP Message WRF_REF001 - Enter at least one plant

Diagnosis
You are trying to select the material/plant combinations to whichreferences are assigned during processing from the database, withoutchange pointers. But you did not enter a selection criterion for theplant.

System Response
To avoid performance problems that are caused by the complete selectionof the material master table, the system does not start the processing.

Procedure
Enter a plant or a range of plants and re-start the processing.