by curt bixel.
Hmmmm... I just successfully backed up a really small course. (2.5MB). That has to be a clue!
But... backing up a single activity from a large class results in hanging again at Confirmation and Review step where it just re-displays the same screen as before, but includes the message:
Filename* You must enter a valid filename for this backup
I included a screen shot below...
The error log shows a message about an orphaned course module associated with the backup that failed, but no orphaned course module for the successful backup.