This problem is solved.
My problem was that I had renamed the downloaded folder, [Microsoft
Internet], upon receipt, to [Microsoft Internet,12/25/99] just
so I could keep track of it. My problem, with Menu OE Help select, vanished
when I restored the original downloaded folder name to [Microsoft Internet]
and now the Menu OE Help works as expected!
The Menu OE Help points to an internal file sequence. In most cases of my
experience, that look similar superficially, changing the name of a
container folder is functionally inconsequential. But in this case, one
must not tamper with names and structure of folders involving the OE 5 help
files.
I have moved my questions to microsoft.public.internet.mail.mac Just by
searching for .mac, one finds several appropriate forums here.