tNetsharingManager访问冲突问题

我正试图编译这个 project 在Delphi2010中,它使用了tNetsharingManager。我导入了类型库并尝试编译它,但不幸的是,我在该函数中遇到访问冲突:

function TNetSharingManager.GetDefaultInterface: INetSharingManager;
begin
  if FIntf = nil then
    Connect;
  Assert(FIntf  nil, 'DefaultInterface is NULL. Component is not connected to Server. You must call "Connect" or "ConnectTo" before this operation');
  Result := FIntf;
end;

(netconlib_tlb的一部分) 错误出现在: if FIntf = nil then 出于某种奇怪的原因……

调用它的代码:

procedure TForm1.GetConnectionList(Strings,IdList: TStrings);
var
  pEnum: IEnumVariant;
  vNetCon: OleVARIANT;
  dwRetrieved: Cardinal;
  pUser: NETCONLib_TLB.PUserType1;
  NetCon : INetConnection;
begin
  Strings.Clear;
  IdList.Clear;
  pEnum := ( NetSharingManager.EnumEveryConnection._NewEnum as IEnumVariant);
  while (pEnum.Next(1, vNetCon, dwRetrieved) = S_OK) do
  begin
     (IUnknown(vNetCon) as INetConnection).GetProperties(pUser);
     NetCon := (IUnknown(vNetCon) as INetConnection);

     if (pUser.Status in [NCS_CONNECTED,NCS_CONNECTING])//remove if you want disabled NIC cards also
     and (pUser.MediaType in [NCM_LAN,NCM_SHAREDACCESSHOST_LAN,NCM_ISDN] )
     and (GetMacAddress(GuidToString(pUser.guidId))'' ) then
     begin
       //we only want valid network cards that are enabled
       Strings.Add(pUser.pszwName );
       IdList.Add(GuidToString(pUser.guidId));
     end;
  end;
end;

我不明白为什么我不能和 零 . 有什么想法吗?