Have you tried searching the support data base? There is a
hot fix service package put out, by Microsoft for this
error occurence in Outlook 2000 I believe.
Give that a shot.
Do you have any anti-virus or firewall software installed? If so, try
turning it off and see if you can send. If that helps, contact the vendor
of the software that was causing the problem and see if they have an update
to fix it.
