Переполнение стека

unit Main;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, jpeg, ExtCtrls, Menus;
 
type
  TFMain = class(TForm)
    MainMenu1: TMainMenu;
    N1: TMenuItem;
    Exit1: TMenuItem;
    N2: TMenuItem;
    N3: TMenuItem;
    N4: TMenuItem;
    N5: TMenuItem;
    N6: TMenuItem;
    N7: TMenuItem;
    N8: TMenuItem;
    N9: TMenuItem;
    N10: TMenuItem;
    N11: TMenuItem;
    N12: TMenuItem;
    N13: TMenuItem;
    N471: TMenuItem;
    N481: TMenuItem;
    procedure Exit1Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure N3Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  FMain: TFMain;
 
implementation
uses Logo, InputNumberGroup, Data;
{$R *.dfm}
 
procedure TFMain.Exit1Click(Sender: TObject);
begin
Close;
end;
 
procedure TFMain.FormShow(Sender: TObject);
begin
FLogo.showmodal;
end;
 
procedure TFMain.N3Click(Sender: TObject);
var ClearTable, FIO: string;
    Num: integer;
begin
 FInputNumberGroup.ShowModal;
 if FInputNumberGroup.ModalResult=mrOk then
  begin
   Num:=0;
   With FData do
    begin
     ClearTable(TData);
     TStudents.IndexName:='FIO';
     TStudents.First;
     While not TStudents.EOF do
      begin
       if TStudents.FieldByName('Ãðóïïà').AsString=NumberGroup then
        begin
         CodeStudent:=TStudents.FieldByName('¹Çà÷¸òêè').AsString;
         FIO:=TStudents.FieldByName('Ôàìèëèÿ.È.Î.').AsString;
         INC(NUM);
        end;
       TStudents.Next;
      end;
     TStudents.IndexName:='¹Çà÷¸òêè';
    end;
   end;
end;
 
end.