I have an old (and long-since discontinued) but good program called
MailKing, which can mail-merge fields from databases and send out
custom emails. I haven't used MailKing for at least a couple of years,
but now I need to send out a newsletter to a mailing list of about a
hundred people.

When I try to do so, MailKing is unable to send the emails. Its Error
Log displays a line such as the following:

not local host alum.mit.edu, not a gateway

where "alum.mit.edu" is the URL portion of the email address for that
particular person.

I'm not sure what that means, nor do I understand why the program
doesn't work now when it always used to. It has relatively crude
set-up options for outgoing email: It just asks for the sender's
(i.e., me) name and email address and Internet Mail Server (i.e., POP
3 mail account).

Can anyone give me a clue as to what you think may be going wrong? Is
MailKing just not up to handling modern day email security protocols?

My computer is running Windows XP, Outlook Express 6.0 (both of which
are more modern versions than I had the last time I used MailKing),
either a dial-up connection or SBC/Yahoo DSL (I've tried both), and
Zone Alarm (I've tried turning it off).