Hope I didn't foul something else up in my site. I see this, now.
Fatal error: Call to a member function on a non-object in /home/content/m/i/s/mistolpatch/html/administrator/components/com_rsgallery2/options/templateManager/helpers/JInstallerRSGTemplate.php on line 49
*** Update: I just reinstalled the build 669 package, same error. Phew, thought I might have done something while I was nosing around controller.php .
I'm finding updates aren't really a problem. Just uninstall / install and paste in the errant "INSERT INTO" statement into phpmysqladmin.