DSNU1255I csect-name UNLOAD IS NOT ALLOWED BECAUSE THE SOURCE IS MISSING THE HEADER PAGE
Explanation
An attempt was made to unload data from a sequential copy data set that does not contain either the header page of the table space or the header page of the partition.
System action
The UNLOAD utility terminates.
Programmer response
Use an image copy data set that contains the header page.
Severity
8 (error)