SMTP name is for the Send Mail Transport Protocol** -- It's the name of a host that will send your message. Take a peek in your regular email program options and you'll probably see the info you need to plug. If that doesn't help perhaps you could discuss with a network admin or whoever set up your email for the correct SMTP (aka SendMail) address.
** exact acronym I'm not sure -- could be Send Mail Transport Program but you get the idea. PKNH