Microsoft has replaced CDONTS with more current technology, CDO/CDOSYS.  As a result, CDONTS components are not installed on our servers, but CDO/CDOSYS components are.  Check Microsoft's Documentation for using CDO/CDOSYS or consider using JMAIL, an extremely easy to use mail component we have installed on our servers.  JMAIL is the 3Essentials recommended solution for sending mail via ASP/ASP.net webpages, and we provide coding samples and complete documentation in the following KB article:

Sending mail from a web page using ASP and JMail