copy this file
C:\Program Files\Common Files\System\ado\adovbs.inc
to your web root directory, then add this line at the top of asp files:
<!--#include virtual="/adovbs.inc" -->
or better yet, add this line at the top of your global.asa file:
<!--METADATA TYPE="typelib" UUID="00000205-0000-0010-8000-00AA006D2EA4" NAME="ADODB Type Library" -->