Activate COM object using website doesn't work in Windows 2003 server

I have been trying really hard to activate and launch a COM object using an ASP.NET web application. The aspx website has a code-behind file that has a reference to this COM object (which is an actual application - a CAD software). When required, the VB code creates (or launches) the application.

The complete set-up works in a Win-XP (32-bit) environment both under debugging using visual studio and when the website is accessed by an outside user (through IIS server in XP). But the same application doesn't get activated when it is hosted onto the Win-2003 (32-bit) IIS server. I get "Object reference not set to an instance of an object" error.

The way I have setup in Win-XP was to grant ASP user and Internet guest user permissions to the COM object in the DCOM Config and since the windows firewall is enabled, I add the exe开发者_StackOverflow中文版 file (associated with the COM object) to the exception list. For the case of Win-2003 server, I add the Network Service permission to the COM object. But the setup doesn't seem to work at all.

I am not sure what I am missing and how to get the application to launch. Any help will be greatly appreciated.

A Couple of things to check:

• Make sure your'e using the ASPNET user, not the old classic ASP user
• Also Apply the ASPNET user and NewtworkService User to the Launch and Activation Permisions in the DCOM Config if you haven't done so already.