Couldn't get mail server response codes

[everettcomstock]

Hey Guys,
    I just re-installed Coppermine on my Win 2000 Server box after a pretty severe crash. I am getting the following error when new users try to register with the site: "Couldn't get mail server response codes ".
    I was wondering if this could have something to do with my web page setup? I am now using virtual hosts that use host-header names instead of IP addresses to transmit info correctly. Could this be the reason for SMTP failure? Any help on this would be greatly appreciated! Thanks!
                                                                                     Everett