"Unable to find project on the Web server. Unable to set Web server into correct debugging state automatically. You may not be able to debug .ASP pages."

After a lot of online research and fiddling with the settings, what follows is what worked for me.

To enable .asp debugging change the following settings:

• In VS.NET:

  
  -------------
     project - properties
        configuration properties
           debugging
              - enable ASP debugging
              - enable ASP.NET debugging
  

• In the IIS snap-in:

  
  ----------------------
     default Website - properties
        home directory tab
           configuration
              app debugging
                 - enable ASP server-side script debugging
  
     Website (the project you want to debug) - properties
        directory tab
           application name: add
  

  This sets an application name for the Website and changes the icon from a default folder icon to a Website icon.
• Add IIS process account to Debugger Users group:

  
  ---------------------------------------------------
     In Computer Management snap-in:
        System Tools
           Local Users and Groups
              Groups
                 Debugger Users - properties
                    Add user IWAM_machine-name (the "Launch IIS process account")
  

• Now, to debug in VS.NET:

  
  ------------------------
     right-click the .asp page that the application should start from
        select "Set as Start Page" 
  
  
     set a breakpoint in the .asp code anywhere in the project
  
     click Debug—>Start or press F5 to build the project and start debugging