Unable to create attachments with SMTP

I am having a problem that seems to be a 98/2000 issue.

I am using (via VB6) the email server (win 2000 - MSExchange) to send smtp email. From my 2000 machine - I can add attachments to the email (usually a pdf) - but from the windows 98 machines, this does not work. Here is a code sample - any ideas what I am doing wrong? On a 98 machine - it bombs on the .addattachment statement.

HELP!!!


Set Flds = IConfig.Fields
IConfig.Load cdoIIS
Flds(cdoSendUsingMethod) = cdoSendUsingPort
Flds(cdoSMTPServer) = "our.server.com"
Flds.Update
Dim imsg As New CDO.Message
Set imsg.Configuration = IConfig
imsg.Sender = Sender
imsg.ReplyTo = Sender
imsg.Subject = EMailSubject
imsg.TextBody = EMailBody
imsg.To = EmailAddress
imsg.AddAttachment AttachmentName$
imsg.Send
Set imsg = Nothing
Set Flds = Nothing
Set IConfig = Nothing


What am I doing wrong????