Plug-in stopped working after 7/9/12 backup. I am not certain, but I may have upgraded to WP 3.4.1 then, so perhaps it is a compatibility issue.
No other setting have changed. Running a manual backup, it tells me that it is complete but doesn't show up in the list or in the Amazon bucket.
I was really liking this plug-in, so I hope it can be brought up to date soon.