Task Scheduler is tricky to get working automatically.  Anything in the Sage activity log? 

The Windows account used to run the job must have proper Windows permissions.

Are orphaned programs left in the Master Console?  (That is one symptom of jobs starting, but not finishing properly... and there are a few reasons for that).

Also make sure the PO batches are not open in a data entry screen (locked), and not marked as Private (ignored by Task Scheduler).

Apparently the printer I'm using for reports must be set to default printer on the server. 

Seems to be working now.

Yes, the Windows default printer for the Windows login used does need to be local (not redirected) and online.  (Paused is fine).  Task Scheduler prints a status report (which we hope Sage will allow us to disable at some point) to that printer, and if it doesn't, the job locks up. 

I believe Paperless also uses the default printer for things like page size during PDF generation.