Security rights needed to invoke a COM object

We are moving our corporate web site from a domain controller running
Windows Server 2003 SP1 to a member server running Windows Server 2003 R2.

The corporate web site is hosting several ASP application, one of those
controls TCP ports assignments on our ISA Server 2004, using ISA provided
COM objects FPC.
The application was created several months ago and is running succesfully on
a directory whose directory security is set to Anonymous authentication and
the Anonymous user is AdminB. AdminB is a Domain Administrator.

Running the same application on the member server the application fails with
error '80070002' .
The anonymous user on the application directory on the member server is
AdminV, that is Domain Administrator as well.
Logging on to the member server with AdminV and running the same COM calls
from a .vbs script from command line the operation succeeds.

If I set my own account on the application directory on the member server
the application succeeds.
Checking the differences group membership between my own account and AdminV
I have found no group that could interfere with those functions, both are
Domain Administrator and as far as I know this should be enough.

If I set AdminB as the anonymous user on the application directory on the
member server the application still fails with the same error.
This suggest some privileges are missing but are not related to group
membership, maybe user rights or some security settings on IIS?

If I set AdminV as the anonymous user on the domain controller the
application fails.

So:
- My account works on both web server
- AdminB work only on the DC web server
- AdminV works nowhere

What's missing?

Any suggestion will be greatly appreciated

Thanks
Gianni Bragante