把DLL 转IDL 在弄成.H .C
但是使用时候报错，不知道怎么回事。

请高手指导。。
这是在VC下的一段代码：
#include <windows.h>
#include <objbase.h>
#include <wininet.h>
#include <Shlobj.h>
………………
      TCHAR wszWallpaper[MAX_PATH];
      HRESULT hr;
      IActiveDesktop *pIAD;
      CoInitialize ( NULL );
      hr = CoCreateInstance((REFCLSID)&CLSID_ActiveDesktop,
       NULL,CLSCTX_INPROC_SERVER,(REFIID)&IID_IActiveDesktop,(LPVOID *)&pIAD );
      if ( SUCCEEDED(hr) )
      {
       hr=pIAD->GetWallpaper (wszWallpaper, MAX_PATH, 0 );
       if ( SUCCEEDED(hr) )
       {
        MessageBox(hwnd,wszWallpaper,"",MB_OK);
       }
       pIAD->Release();
      }
      CoUninitialize();

下面是错误提示：
E:\C FLIES\vc_comtest_c\profile_comtest.c(135) : error C2039: 'GetWallpaper' : is not a member of 'IActiveDesktop'
        c:\program files\microsoft visual studio\vc98\include\shlobj.h(2975) : see declaration of 'IActiveDesktop'
E:\C FLIES\vc_comtest_c\profile_comtest.c(140) : error C2039: 'Release' : is not a member of 'IActiveDesktop'
        c:\program files\microsoft visual studio\vc98\include\shlobj.h(2975) : see declaration of 'IActiveDesktop'

就是编译时候报的错，

编译出错了，还怎么使用啊