Here are some notes I made about moving from CDONTS to CDO that hopefully might help you too.
CDO is generally used instead of CDONTS on IIS 5 and after (actually the SMTP service within IIS) which is generally on servers after Win NT4 (although I think CDONTS is generally still supported too).
Here are changes I made to convert CDONTS stuff to be CDO stuff instead:
o Change objCDONTS to be called objCDO (actually this is just a cosmetic change)
o This:
Set objCDONTS = Server.CreateObject("CDONTS.NewMail")
Changed to this instead:
Set objCDO = Server.CreateObject("CDO.Message")
o This:
objCDONTS.Body = strEmailBody
Changed to this instead:
objCDO.TextBody = strEmailBody
o This removed:
' Importance.
' (0=Low, 1=Normal, 2=High)
objCDONTS.Importance = 1