Com Initialization Error 0x80040154 loading c# COM Object with c++ Program

I'm working on my first COM project that is importing a c# DLL with a C# COM Wrapper class into a C++ native code application. Our application is based on the CSRegFreeCOMServer VS2008 sample project from Microsoft's All-In-One Framework. Our system is using - VS2008, .Net3.5, boost 1.4.2 and Qt 4.6.2.

This application has been running fine on our 32bit XP dev boxes. However, when we load the system onto our Windows 7-64bit system. We cannot get the com objects to initialize. We keep getting error 0x80040154 (which I cannot seem to determine what it means).

Our header file is -

#ifndef ControlComInterface_h__
#define ControlComInterface_h__
#include <string>
#include <ole2.h>    // OLE2 Definitions
// Importing mscorlib.tlb is necessary for .NET components
// see: 
//  http://msdn.microsoft.com/en-us/library/s5628ssw.aspx
#import "mscorlib.tlb" raw_interfaces_only                \
    high_property_prefixes("_get","_put","_putref")        \
    rename("ReportEvent", "InteropServices_ReportEvent")
using namespace mscorlib;
// import the COM Declarations exported com the CSRegFreeCOMServer
#import "..\CSRegFreeCOMServer\bin\Release\CSRegFreeCOMServer.tlb"  no_namespace named_guids
using namespace std;
class ControlComInterface
{
public:
    ControlComInterface(void);
    ~ControlComInterface(void);
    IFieldsPtr spFields;
    IPchFilePtr spPchFileWrapper;
    bool CreateInterfaceObjects(string &errorMsg);
};
#endif // ControlComInterface_h__

The simplified class code is

    #include "ControlComInterface.h"
#include <boost/lexical_cast.hpp>
ControlComInterface::ControlComInterface(void)
    {    }
ControlComInterface::~ControlComInterface(void)
    {    }
bool ControlComInterface::CreateInterfaceObjects( string &errorMsg )
{
HRESULT hr = S_OK;
hr = ::CoInitialize(NULL);  
if (FAILED(hr))
{
    errorMsg = "CoInitialize failed w/err: ";
    errorMsg.append(boost::lexical_cast<string>(hr));
    return false;
    }
errorMsg = "";
hr = spFields.CreateInstance(__uuidof(Fields));
if (FAILED(hr))
    {
    errorMsg = "IFields::CreateInstance failed w/err: ";
    errorMsg.append(boost::lexical_cast<string>(hr));
    return false;
    }
return true;
}

The code is failing with a error code of 0x80040154 on the call to spFields.CreateInstance(...), which just creates an instance of the class in the com object using a default constructor.

Suggestions?