The instructions from the first post worked to create pretty article links, but killed other things in our ISP’s PHP setup like image processing libraries and a host of other things. Time for a rethink of the permalink issue.
The solution comes down to reading in the existing PHP setup (in the form of the php.ini file) from the provider, and then adding on the two lines to fix the permalinks.
I found a nice bit of php code at the script repository B&T’s Tips & Scripts. It reads in the default php.ini file, adds on whatever tweaks you want to make, and then writes out a new custom php.ini file for your web site.
I’m still adding
cgi.fix_pathinfo = 1
cgi.force_redirect = 0
to the end of the php.ini file - things seem to work again.