Finally I could find a solution for my issue, which looks like a Microsoft API issue described in this article: http://support.microsoft.com/kb/218497
actually the API function ADsOpenObject is opening a connection with the server using the credentials you pass but it never close that connection, I tried to close it but it doesn't became close in the session, so I used another API to check the existence of the object first, check out this function it worked for me:
procedure ShowADSPath(UserName, Password: widestring);
function CheckObject(APath: String): IDispatch;
var
Moniker: IMoniker;
Eaten: integer;
BindContext: IBindCtx;
Dispatch: IDispatch;
begin
Result := nil;
OleCheck(CreateBindCtx(0, BindContext));
OleCheck(MkParseDisplayName(BindContext, PWideChar(WideString(APath)),
Eaten, Moniker));
OleCheck(Moniker.BindToObject(BindContext, nil, IDispatch, Dispatch));
Result := Dispatch;
end;
var Group : IADs;
begin
try
if CheckObject('WinNT://Server/Group1,group') <> nil then
OleCheck(ADsOpenObject('WinNT://Server/Group1,group',
UserName,
Password, ADS_SECURE_AUTHENTICATION, IADs, Group));
if (Group <> nil) and (Group.Class_ = 'Group') then
begin
ShowMessage(Group.ADsPath);
Group.release;
Group:= nil;
end;
except
ShowMessage('NOT ACCESSDE');
end;
end;