C Error

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT ps;
    HDC hdc;
    BITMAP bm;
    HBITMAP hbmOld;
    HDC hdcMem;
    switch (message)
    {
    case WM_COMMAND:
        wmId    = LOWORD(wParam);
        wmEvent = HIWORD(wParam);
        // Parse the menu selections:
        switch (wmId)
        {
        case IDM_ABOUT:
            DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
            break;
        case IDM_EXIT:
            DestroyWindow(hWnd);
            break;
        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
        }
        break;
    case WM_CREATE:
        g_hbmBall = LoadBitmap(GetModuleHandle(NULL), MAKEINTRESOURCE(ID_V6));
        if(g_hbmBall == NULL)
            MessageBox(hWnd, L"Could not load IDB_BALL!", L"Error", MB_OK | MB_ICONEXCLAMATION);
        break;
    case WM_PAINT:
            hdc = BeginPaint(hWnd, &ps);
            hdcMem = CreateCompatibleDC(hdc);
            hbmOld = (HBITMAP)SelectObject(hdcMem, g_hbmBall);
            GetObject(g_hbmBall, sizeof(bm), &bm);
            BitBlt(hdc, 0, 0, bm.bmWidth, bm.bmHeight, hdcMem, 0, 0, SRCCOPY);
            EndPaint(hWnd, &ps);
        break;
    case WM_DESTROY:
        SelectObject(hdcMem, hbmOld);
        DeleteDC(hdcMem);
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}