Jake Savin at Radio Userland realized what the problem was, and issued a permanent fix:
It appears as though you (and others?) didn't have the latest version of radio.backup.backupTemplates. I've re-released the latest version of this part, which should fix the errors.
You may want to re-add the @statusMsg parameter to the call to the radio.backup.backupTemplates call in radio.backup.backupAll, to make sure that you see any error messages that may occur when backing up your templates.
I received Jake's radio.root update early this morning and posted my results back to the discussion thread:
Talk about some lucky timing - my nightly backup completed at 12:21 AM and then I got Jake's root update at 12:25 AM.
I re-added the @statusMsg parameter to the radio.backup.backupTemplates call in radio.backup.backupAll, re-compiled the macro, then did a manual backup. No errors.
I won't know until tomorrow if the nightly backup works too, but I'm not expecting any problems.
Not a big deal, but I wonder how I ended up with a non-current version of the radio.backup.backupTemplates macro.
Thanks for fixing this, Jake!