Sorry, Tuesday’s uninstall then reinstall (of 2.0.2.9) resolved the issue. But when it wasn’t working I could find no CoCoL.dll in either the Program Files or Windows trees.
My assumption was that a failed (something in use, reboot requires) in-app upgrade from 2.0.2.8 to 2.0.2.9 had gotten as far a removing old version files but not installing the new versions.
I assume it doesn’t do any good to give you the DLL version on the working copy…