Problems loading XACT global settings

I am trying to load and register global settings data with XACT. This is the code i am currently using to initialise XACT.

 

        pEngine = NULL;

	//No creation flags yet
	DWORD dwCreationFlags = 0;

	//Initialise COM object
        CoInitialize(NULL);

	//Create engine object
	XACTCreateEngine(dwCreationFlags, &pEngine);


    // Initialize & create the XACT runtime 
	VOID* pGlobalSettingsData = NULL;
        DWORD dwGlobalSettingsFileSize = 0;
	DWORD dwBytesRead = 0;

      HANDLE	hFile = CreateFile("Sounds.xgs", GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
        if( hFile )
        {
            dwGlobalSettingsFileSize = GetFileSize(hFile, NULL);
            if( dwGlobalSettingsFileSize != INVALID_FILE_SIZE )
            {
                pGlobalSettingsData = CoTaskMemAlloc(dwGlobalSettingsFileSize);
                if( pGlobalSettingsData )
                {
                   ReadFile(hFile, pGlobalSettingsData, dwGlobalSettingsFileSize, &dwBytesRead, NULL);
                   
                }
            }
            CloseHandle( hFile );
        }


    // Initialize & create the XACT runtime 
    XACT_RUNTIME_PARAMETERS Params = {0};
    Params.pGlobalSettingsBuffer = pGlobalSettingsData;
    Params.globalSettingsBufferSize = dwGlobalSettingsFileSize;
    Params.globalSettingsFlags = XACT_FLAG_GLOBAL_SETTINGS_MANAGEDATA; 
    Params.lookAheadTime = 250;

	

	//Initialise IXACT engine object
	HRESULT Result = pEngine->Initialize(&Params);
	assert(Result == S_OK);

pEngine isn't initialised properly when the pGlobalSettingsBuffer and pGlobalSettingsBufferSize are set, and passed to the initialize function. It works fine when no params are passed. Can anyone tell me if i'm missing anything or doing something wrong? Thanks