by Ken Task.
Debug normally shows on the screen ... but copying a course is a background process so it might not show ... dunno for sure ... not having the issue.
Did you look in moodledata/temp/backup/ for a folder and what's in that folder? The copy process makes use of backup, then restores. Anything left in there?
How about when you run cron .... adhoc_task ... any 'hung' adoc_task related?
Last offer ... check your PM on this system!
'SoS', Ken