[fetchmail] fetchmail synchr/socket error

I execute "fetchmail" with the following .fetchmailrc

        set spambounce
        poll    wdn.com 
        proto AUTO
        user "sam"
        password "mypassword"
        keep

No matter what I try in an attempt to read new messages, Fetchmail
hangs up on the first unread message in my server's store.  Error
message: "socket error while delivering to SMTP host myISPdomain".    I
have no problem accessing my messages via Mozilla (but not Netscape),
which may be a clue.

I am using:

    Linux 2.2.20       Debian woody (3.0) 
    Debian Woody (3.0) 
    fetchmail6.2
     mutt
     exim3.35
     
with ISP Irides
     
I've tried to get help on this earlier and thank those who responded. 
During my attempts to troubleshoot the problem all my then current
messages were obliterated.

Thanks,

sam