Debuggin ISAPI dll in delphi 2006 fails when dll instatiated via COM

Question

We have a delphi ISAPI dll web app that runs in IIS. The application allows extensions via a COM object that ASP pages can instantiate (the com object resides within the ISAPI dll). When we are debugging, as soon as an ASP page is called that instantiates the COM object debugging fails, no more breakpoints will work.

This problem only presents itself in Windows 7. Debugging on windows XP works fine. (Problem is we cannot continue to develop on XP!) Any insight into what might be causing this would be appreciated.

Note we are using Delphi 2006

Answer 1

I remember for debugging on Windows XP I would set the isolation level to high, and start the dllhost.exe myself for the ApplicationID that is automatically generated by IIS in the COM+ system.

On Windows 7 and the new IIS, this section is revised and IIS now runs its own w3wp.exe processes grouped in application pools. Check the isolation settings and maximum processes of the Application Pool your ASP project (or ISAPI extension?) and try to either start the w3wp.exe process yourself with the correct parameters or attach to the one that is started.