After several weeks of trying, the backup (wbadmin) doesn't work from the task scheduler. When I enter the WBADMIN Start Backup command directly into a command prompt, it executes perfectly and backs up everything it's supposed to, but for some reason, when that EXACT SAME COMMAND is executed from the task scheduler it starts, then immediately stops. I opened the Task Scheduler, clicked on "Task Scheduler Library" in the left pane, and looked at the backup job in the top window of the center pane. The "Last Run Result" column simply showed, "(0xFFFFFFFF")". I also clicked on the job's History Tab, which showed 7 entries at the date/time the job is set to trigger, which indicated that the task started and completed, "successfully" within the same second (i.e. 01:00:00), but absolutiely nothing is backed up, nor are there any entries for the trigger date on the backup drive.
This has happened four Sundays in a row, and each time, when I subsequently execute the WBADMIN command from a command prompt, it works correctly. Any ideas about what I'm missing and/or doing incorrectly