B) Have you tried both just the user name, and also the full email address? (IE: kingu and kingu@someplace.net) - many providers have recently switched to requiring the full e-mail address.
C) If this is a work e-mail, is the POP port available on your company's network for access outside of the corporate network? Or do they require you use IMAP access?
att, it uses a yahoo server
pop.att.yahoo.com
smtp.att.yahoo.com
the ports are the same 946 and 442 or somethign like that
ssl
I always had to use my full address with @att.net