At last! Apparently my account key was out of date, so I had to go back
to "uacme -v new", but after that, and after a few tries (server is very
busy, as someone mentioned recently) I got my certificate. Now I just
have to set up scheduling to get a new certificate after 80 days.
Thanks to Massimo and especially Steven for identifying obsolete DLLs as the
probably cause of the problem.
It took me a couple of hours to update the DLLs, because I took a
roundabout route. I had an old version of ANPM on that machine, and I
tried to use that to update curl. That kept failing and reporting a
chain of unresolved conflicts, which I think boiled down to LIBCURL
requiring an unavailable CURL4.DLL; but I didn't manage to find out what
package CURL4.DLL is in.
Then I tried to install an updated ANPM. That failed because it requires
WarpIn 1.0.24, and OS2Site (the only Hobbes substitute I know about)
only has 1.0.22. Web search results, including the Netlabs one, all tell
you to get it from Hobbes.
So I finally did what I should have done in the first place, which was
to try "yum update curl". Although this didn't work, adding an extra
option (something like -ignore-conflicts) did work. I got a checksum
error on one package, but apparently that wasn't vital.