Any difference regarding remote COM server activation on Windows 7 vs on Windows XP?

I'm studying Microsoft COM technology from the book Learning DCOM 1999. I am puzzled with its Hello Universe sample program in Appendex D. The code is available here.

This sample contains a HelloClient.exe and a HelloServer.exe. They can be run on different Windows machines and HelloClient.exe is able to remotely call server's exposed IHello interface.

I tried HelloServer.exe on Windows XP and the HelloClient.exe on Win7 successfully call into the remote object.

However, when HelloServer.exe is run on Windows 7, the remote client always fails on CoCreateInstanceEx(CLSID_Hello, ...) with 0x80040154 (Class not registered).

So I think there must be some change since Windows Vista/7 that causes the failure.

Then what is the change, or, what am I missing?

BTW: I compile the code using Visual Studio 2010 SP1.