And suddenly, I have it working!
Only thing I did differently this time was to delete the previous tgz file from the .kobo directory - even though it had the same file creation date of 7/21, that seemed to do the trick! Very weird.
Thanks everyone for helping.
I wish I'd asked for help in the first place instead of doing all the resets and losing my badges and reading history. Ho hum. It was just five months worth, will be easy to build it up again.