Field value required

Hello

A have a client/server application. Server runing as Windows Service, the client is an Android App.

On Server side i have a function, getAmef with this code:
procedure Tdmactivserver.getAmefExecute(Sender: TRtcConnection;
  Param: TRtcFunctionInfo; Result: TRtcValue);
var tip:integer;
qr:tfdquery;
rtcDS: TRtcDataSet;
begin
  logfile('Citire casefiscale', '!', '!');
  if Param.isNull['tip'] then
   raise Exception.Create('Parametru TIP lipseste!')
  else tip:=param.asInteger['tip'];

  case tip of
  1: logfile('Tip case: AMEF FISCALIZATE' , '!', '!');
  2: logfile('Tip case: AMEF NE-FISCALIZATE', '!', '!');
  else begin
   logfile('Tip case: '+tip.ToString, '!', '!');
   raise Exception.Create('Parametru TIP cu erroare!');
  end;
  end;

  try
   qr:=tfdquery.Create(self);
   qr.Connection:=db;
   try
   case tip of
   1: begin
   qr.SQL.Add('SELECT c.seria, cast(c.aviz as char(10)) aviz, c.dataachizitie, c.configuratia, c.fiscalizata, c.idclient, c.idpctl, c.NUI, c.datavanzare, c.achizitieproprieclient, cl.denumire utilizator, pl.adresa');
   qr.SQL.Add(', pl.localitatea, pl.judet, cl.tel1, cl.sms FROM casefiscale c');
   qr.SQL.Add('left join clienti cl on cl.id=c.idclient');
   qr.SQL.Add('left join punctedelucru pl on pl.id=c.idpctl');
   qr.SQL.Add('where c.fiscalizata=1 order by cl.denumire');
   end;
   2: begin
   qr.SQL.Add('SELECT c.seria, cast(c.aviz as char(10)) aviz, c.dataachizitie, c.configuratia, c.fiscalizata, c.idclient, c.idpctl, c.NUI, c.datavanzare, c.achizitieproprieclient, cl.denumire utilizator, pl.adresa');
   qr.SQL.Add(', pl.localitatea, pl.judet, cl.tel1, cl.sms FROM casefiscale c');
   qr.SQL.Add('left join clienti cl on cl.id=c.idclient');
   qr.SQL.Add('left join punctedelucru pl on pl.id=c.idpctl');
   qr.SQL.Add('where c.fiscalizata=1 order by cl.denumire');
   end;
   end;
   qr.Open();
   logfile('Inregistrari='+qr.RecordCount.ToString, '!', '!');
   rtcDS := TRtcDataSet.Create;
   try
   DelphiDataSetToRtc(qr, rtcDS);
   Result.asObject := rtcDS;
   except
   on E:EDatabaseError do begin
   logfile(e.Message, 'Exception', 'getAMEF.rtcDs');
   rtcDS.Free;
   end;
   end;
   except
   on E:EDatabaseError do begin
   logfile(e.Message, 'Exception', 'getAMEF.qr');
   end;
   end;
  finally
   qr.Close;
   qr.Free;
  end;

end;

On the client side, function request is:
procedure TfrmAmef.Button4Click(Sender: TObject);
var tip:integer;
begin
   if sw1.IsChecked then tip:=2
   else tip:=1;

   // amef
   log.d('Request Amef');
   log.d('Tip='+tip.ToString);

   //dm.RtcClientModule.CancelRequests;
   with dm.RtcClientModule do begin
   data.Clear;

   with data.NewFunction('getAmef') do begin
   param.asInteger['tip']:=tip;
   end;

   try
   call(dm.rtcResult1);
   except
   on e:exception do begin
   log.d(e.message);
   end;
   end;
   end;

end;

The result side is:
else
if (Data.isType=rtc_Function) and (Data.asFunction.FunctionName='getAmef') then begin
log.d('Rezultat la '+Data.asFunction.FunctionName);
if Result.isType = rtc_Dataset then begin
log.d('+');
rtcMamef.Close;
try
rtcMamef.asDataSet := Result.asDataSet;
Result.Extract;
rtcMamef.Open;
log.d('Recno='+rtcMamef.RecordCount.ToString);
except
on e:exception do
log.D(e.Message);
end;
end
else
end

First problem is this, and i can't figure out how to solve it:
rtcMangDs is an rtcclientdatasource.

If I try to manage the fields (with the field manager), log.d displays the error message Field value required.
If I do not add any field in the field manager, I receive the correct answer and and everything works.

The second problem, o functions on server side,
if one field is index key, unique, unsigned, I have to do CAST on it to be able to work with that field in field manager.

How can I handle these problems, especially since the former holds me in down.
With thanks

Field value required.