CoCreateInstance - Class not registered

I'm following the following tutorial:
http://www.codeguru.com/cpp/com-tech/activex/tutorials/article.php/c5567

I have built the dll and I am trying to run the client C++ program to access the dll.

CodeGuruMathLib::IAddPtr pFastAddAlgorithm;
pFastAddAlgorithm.CreateInstance("CodeGuru.FastAddition");

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First of all:
1. My dll is registered properly as I add the following in the post build event: regsvr32 ..\Debug\AddObj.dll
2. When I look in the registry I see the entry:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{92E7A9C2-F4CB-11D4-825D-00104B3646C0}\ProgId\CodeGuru.FastAddition
so this indicates to me that it has registered properly.

Now when I step into the function pFastAddAlgorithm.CreateInstance above I get to:
hr = CoCreateInstance(rclsid, pOuter, dwClsContext, __uuidof(IUnknown), reinterpret_cast<void**>(&pIUnknown));
but hr = Class not regstered.

Why could this be??

Thanks