[HV-Adam]

CDOSYS is a replacement for CDONTS and should be used instead of it. 
CDONTS has been removed from Windows 2003 and is no longer supported 
in Server 2003. A working example is below:

Dim objMsg 
Dim objConfig 
Set objMsg = CreateObject("CDO.Message") 
Set objConfig = CreateObject("CDO.Configuration") 
Dim objFields 
Set objFields = objConfig.Fields 
' Setup server information. Comment out if using localhost
objFields("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "mail.mysmtpserver.com" 
objFields("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25 
objFields("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2 

' Setup server login information if your server require it. Comment out if using localhost
objFields("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate") = 1 
objFields("http://schemas.microsoft.com/cdo/configuration/sendusername") = "SMTPAUTHUser" 
objFields("http://schemas.microsoft.com/cdo/configuration/sendpassword") = "SMTPAUTHPassword" 

'uncomment if using localhost.
'objFields("http://schemas.microsoft.com/cdo/configuration/sendusing") = 1
'objFields("http://schemas.microsoft.com/cdo/configuration/smtpserverpickupdirectory")="c:\inetpub\mailroot\pickup"

objFields.Update

' Now you can setup message to send 
Set objMsg.Configuration = objConfig 
objMsg.To = "tosomeone@somewhere.com" 
objMsg.From = "fromme@domain.com" 
objMsg.Subject = "Some subject" 
objMsg.TextBody = txMessage 

objMsg.Send
set objMsg = NOTHING