CoCreateInstance returns REGDB_E_CLASSNOTREG (IMAPI)

Question

Hi, i'm trying to accessing IMAPI from a Managed C++ Windows Form Control Library

the problem is that when i call CoCreateInstance  i get in return REGDB_E_CLASSNOTREG.
I Really dont understand why since the equivalent code from a .NET imapi wrapper that works is identical. notice also that the same C++ code here works on another machine.
i assume also that the class is correctly registered since the C# code works.
thanks to anyone who try to help

My C++/CLI code:
[code]
CLSIDFromString(L"{520CCA62-51A5-11D3-9144-00104BA11C5E}", &CLSID_MSDiscMasterObj);
CLSIDFromString(L"{520CCA62-51A5-11D3-9144-00104BA11C5E}", &IID_IDiscMaster);

CoInitialize( NULL );

hr = CoCreateInstance(CLSID_MSDiscMasterObj, nullptr, CLSCTX_INPROC_SERVER | CLSCTX_LOCAL_SERVER, IID_IDiscMaster, (void**)&m_pDiscMaster); //REGDB_E_CLASSNOTREG
[/code]


working C# code
[code]
object discMaster = null;
Guid clsIdDiscMaster = new Guid(CLSID_MSDiscMasterObj);
Guid iidDiscMaster = new Guid(IID_IDiscMaster);
int hResult = IMAPIObjectFactory.CoCreateInstance(ref clsIdDiscMaster, IntPtr.Zero, CLSCTX.CLSCTX_INPROC_SERVER | CLSCTX.CLSCTX_LOCAL_SERVER, ref iidDiscMaster, out discMaster);
[/code]

where CoCreateInstance is
[code]
        [DllImport("ole32", CharSet = CharSet.Unicode)]
        private extern static int CoCreateInstance(
            ref Guid CLSID,
            IntPtr pUnkOuter,
            CLSCTX dwClsContext,
            ref Guid IID,
            [MarshalAs(UnmanagedType.Interface)]
            out object ppv);
[/code]

Answer 1

It is not equivalent code.  In the C# code, you ask IMAPIObjectFactory to create the class object for you.  You need to duplicate that in C++, find out how to create the IMAPIObjectFactory object.

Answer 2

IMAPIObjectFactory only encapsulate CoCreateinstance nothing more.
anyway i tried changed

From:
CoCreateInstance(CLSID_MSDiscMasterObj, 0, CLSCTX_ALL, IID_IDiscMaster, (void**)&m_pDiscMaster); //REGDB_E_CLASSNOTREG

To:
CoCreateInstance(__uuidof(MSDiscMasterObj), 0, CLSCTX_ALL, IID_IDiscMaster, (void**)&m_pDiscMaster); //OK

it seems to solve the problem...thx