SAP Message QACT009 - Error when generating/updating worklist

Diagnosis
You want to generate/update the worklist. An error occurred whenwriting the data to the database.

System Response
The system could not generate/update the worklist.

Procedure
Find out the cause of the error and remove it. To do this, read thesystem log (transaction SM21). Contact the system administrator ifnecessary.
After you have removed the cause of the error, restart the function'Create worklist'.