Do I have to specify a valid userid in the "Requesting User ID" field of the DSPSLOG panel?
No, it is not required that you specify a userid in the "Requesting User ID" field of the DSPSLOG panel. You need only specify a valid userid should you decide to filter the transfers using that userid. Make sure to specify the userid in the proper case (e.g. lower or upper case) to get the proper results back.