exim/fetchmail config

[Jeff Elkins <jeff@elkins.org>]

I've recently switched to a system where fetchmail picks up all my pop3 email 
and routes it to a local address, wherespamassassin analyzes it. Thus far, 
it's been working great, except for one caveat...

Certain family members are Windows/Outlook Express users and when they attempt 
to reply to an email it's routed to jeffelkins@localhost or jeff@localhost 
rather than jeffelkins(at)earthlink.net or jeff(at)elkins.org 

Thus their replies bounce.

I'm stumped. Is this a problem with my exim/fetchmail config or is it a OE 
problem?  How can I overcome this?

(this is a resend...please assist if you can)

TIA

Jeff Elkins