// This class is exported from the ndisapi.dll
class NDISAPI_API CNdisApi
CNdisApi (const TCHAR* pszFileName = _T(DRIVER_NAME_A));
//CNdisApi (const TCHAR* pszFileName = (DRIVER_NAME_A);
virtual ~CNdisApi ();
The problem caused by -DUNICODE compiler switch. If you want your project to use UNICODE then you have to recompile ndisapi.dll as UNICODE either. For backward compatibility with earlier versions of Windows ndisapi.dll distributed within WinpkFilter package is built as multibyte.