Could not install the Permalink plugin because I couldn’t log-in to the dashboard. Which I haven’t seen an answer to as of yet.
BUT realized that the database update I was being forced to do after back-installing to 3.0.5 wasn’t a forced version update. Was then finally granted access the dashboard.
Used that opportunity to activate the permalink plug-in THEN updated to 3.1.
THAT solved it.
However this edit does NOT solve the problem. (As I then went and disabled the plug-in to test the canonical edit and ran into the same problem.) Just for the record.
So it would seem… installing an old version is a surefire (if not the only) way to address this problem if you can’t log in to your dashboard.
Neat.