Erro de violation no relatório...ao executar na segunda vez!

var
  frmLisRelPraSemanais: TfrmLisRelPraSemanais;
  data, HorIni, HorFin, aluno, Inst, Cat :TQRLabel;
   i, a, b, c, d, e, Cont, soma, x, y, z :integer;
   SomaData, HrF : Integer;

implementation

uses fdtmiza, FRelPraSemanal, Praticas, FRelSemanal, IBQuery, FPrincipal, FPesquisa, funcoes;

{$R *.dfm}

procedure TfrmLisRelPraSemanais.spbfecClick(Sender: TObject);
begin
  Close;
end;

procedure TfrmLisRelPraSemanais.spbexiClick(Sender: TObject);
begin


  Application.CreateForm(TQrSemanal,QrSemanal);

   // Coluna das Datas
   for i:=1 to 7 do
      begin
        data                   := TQRLabel.Create(self);
        data.Name              := ´Dat´+inttostr(i);
        data.Left              := -40+(i*135);
        data.top               := 50;
        data.Frame.DrawTop     := true;
        data.Frame.DrawBottom  := true;
        data.Frame.DrawLeft    := true;
        data.Frame.DrawRight   := true;
        data.Transparent       := true;
        data.Width             := 130;
        data.Font.Size         := 12;
        data.Height            := 21;
        data.Font.Name         := ´Arial´;
        data.Font.Style        := [fsBold];
        data.AutoSize          := false;
        data.Caption           := DateToStr(DataInicial.Date-1 + i);
        data.Alignment         := TaCenter;
        data.Parent            := QrSemanal.QRBand1;
      end;

 // coluna de horarios
   for a:=1 to 16  do
      begin
        HorIni                   := TQRLabel.Create(self);
        HorIni.Name              := ´Hor´+inttostr(a);
        HorIni.Left              := 4;
        HorIni.Height            := 23;
        HorIni.Frame.DrawTop     := true;
        HorIni.Frame.DrawBottom  := true;
        HorIni.Frame.DrawLeft    := true;
        HorIni.Frame.DrawRight   := true;
        HorIni.Transparent       := true;
        HorIni.AutoSize          := false;
        HorIni.Width             := 43;
        HorIni.Font.Size         := 10;
        HorIni.Font.Name         := ´Arial´;
        HorIni.Font.Style        := [fsBold];
       // hora.Caption           := inttostr(6+a)+´:00´;
        HorIni.Caption           := ´´;
        HorIni.Alignment         := tacenter;
        HorIni.top               := 50+(a*25);
        HorIni.Parent            := QrSemanal.QRBand1;
      end;

 // coluna de horarios
   for HrF:=1 to 16  do
      begin
        HorFin                   := TQRLabel.Create(self);
        HorFin.Name              := ´HorFin´+inttostr(HrF);
        HorFin.Left              := 50;
        HorFin.Height            := 23;
        HorFin.Frame.DrawTop     := true;
        HorFin.Frame.DrawBottom  := true;
        HorFin.Frame.DrawLeft    := true;
        HorFin.Frame.DrawRight   := true;
        HorFin.Transparent       := true;
        HorFin.AutoSize          := false;
        HorFin.Width             := 43;
        HorFin.Font.Size         := 10;
        HorFin.Font.Name         := ´Arial´;
        HorFin.Font.Style        := [fsBold];
       // hora.Caption           := inttostr(6+a)+´:00´;
        HorFin.Caption           := ´´;
        HorFin.Alignment         := tacenter;
        HorFin.top               := 50+(HrF*25);
        HorFin.Parent            := QrSemanal.QRBand1;
      end;


         //criacao do QrLabel do Instrutor
        begin
          Inst                   := TQRLabel.Create(Self);
          Inst.Name              := ´Ins´;
          Inst.Left              := 104;
          Inst.top               := 480;
          Inst.Frame.DrawTop     := true;
          Inst.Frame.DrawBottom  := true;
          Inst.Frame.DrawLeft    := true;
          Inst.Frame.DrawRight   := true;
          Inst.Transparent       := true;
          Inst.AutoSize          := false;
          Inst.Width             := 300;
          Inst.Font.Size         := 12;
          Inst.Font.Name         := ´Arial´;
          Inst.Parent            := QrSemanal.QRBand1;
        end;

   soma := 0;
   for b:=1 to 16  do // total de aluno um em baixo do outro
     for c := 1 to 7 do // total de coluna de aluno
        begin

        soma := Soma + 1;
          aluno                   := TQRLabel.Create(Self);
          aluno.Name              := ´Al´+inttostr(soma);
          aluno.Left              := -40+(c*135);
          aluno.top               := 50+(b*25);
          aluno.Frame.DrawTop     := true;
          aluno.Frame.DrawBottom  := true;
          aluno.Frame.DrawLeft    := true;
          aluno.Frame.DrawRight   := true;
          aluno.Transparent       := true;
          aluno.AutoSize          := false;
          aluno.Width             := 130;
          aluno.Font.Size         := 9;
          Aluno.Height            := 22;
          aluno.Font.Name         := ´Arial´;
          Aluno.Font.Style        := [fsBold];
          aluno.Caption           := ´´;
          aluno.Parent            := QrSemanal.QRBand1;
        end;

      //mostrar o nome do instrutor
     With DtmIza.QryPraticas do
        begin
          close;
          sql.Clear;
          sql.add(´Select Codigo, Nome from Instrutores where codigo =´+ TxtInst.Text);
          open;
        end;
     If  not DtmIza.QryPraticas.IsEmpty then
          begin
             TQRLabel(FindComponent( ´Ins´ )).Caption := DtmIza.QryPraticas.FieldByName(´Nome´).AsString;
          end;


   // pesquisa de Horarios
   with dtmiza.QryIza do
     begin
       close;
       sql.clear;
       sql.add (´Select HorarioInicial, HorarioFinal, Instrutor from HorariosPraticas where Instrutor =:Ins´);
       ParamByName(´Ins´).AsString := TxtInst.Text;
       open;
     end;
   Cont := 1;
   while not dtmiza.QryIza.Eof do
     begin
       TQRLabel(FindComponent( ´Hor´ + IntToStr(Cont))).Caption := FormatDateTime(´hh:nn´, dtmiza.QryIza.FieldByName(´HorarioInicial´).AsDateTime);
       TQRLabel(FindComponent( ´HorFin´ + IntToStr(Cont))).Caption := FormatDateTime(´hh:nn´, dtmiza.QryIza.FieldByName(´HorarioFinal´).AsDateTime);
       DtmIza.QryIza.Next;
       Cont := Cont + 1;
     end;

   // pesquisa de alunos
   for x:=1 to 16 do
   begin
      for y:=1 to 7 do
      begin
        z:=z+1;

        if  TQRLabel(FindComponent( ´Hor´ + IntToStr(x))).Caption <>´´ then
        begin
          DtmIza.QryPraticas.close;
          DtmIza.QryPraticas.sql.Clear;
          DtmIza.QryPraticas.sql.Add(´select p.instrutor, p.horario, p.data, p.aluno, p.bloqueado, a.codigo, a.nome from praticas p, alunos a´
                                     +´ where instrutor =:inst and horario =:hor and data =:dat and p.aluno = a.codigo´);
          DtmIza.QryPraticas.ParamByName(´Inst´).AsString := TxtInst.Text;
          DtmIza.QryPraticas.ParamByName(´dat´).AsDate    := StrtoDate(TQRLabel(FindComponent(´Dat´ + IntToStr( y ) ) ).Caption);
          DtmIza.QryPraticas.ParamByName(´hor´).AsTime    := StrToTime(TQRLabel(FindComponent( ´Hor´ + IntToStr(x))).Caption);
          DtmIza.QryPraticas.open;
        end;

    if not DtmIza.QryPraticas.IsEmpty then
        begin
          if DtmIza.QryPraticas.FieldByName(´Bloqueado´).AsString = ´S´ then
            begin
              TQRLabel(FindComponent( ´Al´ + IntToStr(z))).Caption:= ´ **********************´;
            end;
            //else
           // begin
              TQRLabel(FindComponent( ´Al´ + IntToStr(z))).Caption := ´ ´ + DtmIza.QryPraticas.FieldByName(´nome´).asstring;
           // end;
       end;
     end;
   end;


   QrSemanal.Preview;
   QrSemanal.Free;
   DtmIza.QryPraticas.close;
   close;


 end;