I've been getting this error on both my Mac Mountain Lion as well as my Windows 7 64 bit machine. Everything was working until a couple of days ago, but now nothing is getting backed up.
There was a brief maintenance cycle during the timeframe of your post. Looking at logs associated to your account the failed backups correspond to one 24 hour cycle. It doesn't explain why the backups were failing beyond 11/28. I also noticed it seems you have two sets of the exact same name. The key difference appears to be one stopped backing up on 12/2 and the new one started on 12/3.
Did you remove the software and create a new Computer recently?
If yes, this may limit my ability to further diagnose the issue other than asking if you're seeing this surfacing on any other sets.
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