Final update: replacing the lines indicated in the previously-linked post got me past the error message in the panel, but the install did not work. I copied the system.reg from my (originally 1.1.14, upgraded to 1.1.15) installation and it worked, though it seemed to have a bunch of junk in it (applications installed on the other machine showed up as available for uninstall). It appears that the problem is simply that Wine 1.1.15 will not create a valid system.reg from scratch. 1.1.14 did. At least there is an open bug and someone will address this, eventually.
