To use the ADO constants, you've probably added this piece of code to each of your ASPs:
<!-- #include file='adovbs.inc'-->
If you write reusable data access ASP code, you might have seen the problem where putting the server side include in each file resulted in a "constant redefined" error. A better way to solve this is by adding a project reference. Like Visual Basic, Visual Interdev allows you to add ActiveX components to the project. After you create a VI6 project, click the Projects menu and then select References. Select the ADO 2.x Library in the dialog box and hit okay. If you open the global.asa file, you'll notice that VI6 added some special tags. Now, you can use the ADO constants throughout your Web application without that server side include.