خطأ في القيمة المرجعة من دالة حال اسنادها الى متغير

كود :
unit UnitMain;

interface

uses
    System.SysUtils, Vcl.Graphics,  Vcl.Forms,  Winapi.Windows,
     Vcl.Dialogs, Vcl.Controls, Vcl.StdCtrls, System.Classes,  Winapi.Messages, System.Variants;

type
  TForm2 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    btnModify: TButton;
    Label1: TLabel;
    btnSelectWorkFile: TButton;
    btnSelectBadFile: TButton;
    Label2: TLabel;
    Label3: TLabel;
    OpenDialog1: TOpenDialog;
    SaveDialog1: TSaveDialog;
    lblAuthor: TLabel;
    procedure btnModifyClick(Sender: TObject);
    procedure btnSelectWorkFileClick(Sender: TObject);
    procedure btnSelectBadFileClick(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
   // procedure btnModifyExit(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;

implementation

{$R *.dfm}
uses unitLogin;

Type
  ByteArray = array of Byte;
//=============================================


procedure notCorrectFile(okFile, badFile: string; var isErr: Boolean);
var
  MS1, MS2: TMemoryStream;
  okFileVal, badFileVal: integer;
begin
  MS1 := TMemoryStream.Create;
  MS2 := TMemoryStream.Create;
   try
     MS1.LoadFromFile(okFile);
     MS1.Seek($00FE0008, soFromBeginning);
     MS1.Read(okFileVal, 3);
     MS2.LoadFromFile(badFile);
     MS2.Seek($00FE0008, soFromBeginning);
     MS2.Read(badFileVal, 3);
     if IntToHex(okFileVal, 3) <> '304D43' then
     begin
       ShowMessage('Choose correct work file for Tdvr4i !');
       isErr := True
     end
     else if IntToHex(badFileVal, 3) <> '304D43' then
     begin
       ShowMessage('Choose correct bad file for Tdvr4ii !');
       isErr := True;
     end
     else
   finally
     begin
       MS1.Free;
       MS2.Free;
     end;
   end;
end;

//==============================================================================
function read_(FileName : string; Offset : DWORD; Length : DWORD; out bArray : ByteArray): Integer;
var
  MS : TMemoryStream;
begin
  MS := TMemoryStream.Create;
  try
    MS.LoadFromFile(FileName);
    MS.Position := Offset;
    SetLength(bArray, Length);
    Result := MS.Read(bArray[0], Length);
  finally
    MS.Free;
  end;
end;
//==============================================================================
function write_(FileName : string; Offset : DWORD; var bArray : ByteArray): Integer;
var
  MS : TMemoryStream;
begin
  Result := 0;
  MS := TMemoryStream.Create;
  try
    MS.LoadFromFile(FileName);
    MS.Position := Offset;
    Result := MS.Write(bArray[0], Length(bArray));
    MS.SaveToFile(fileName);
  finally
    MS.Free;
  end;
end;
//==============================================================================
procedure TForm2.btnSelectWorkFileClick(Sender: TObject);
begin
  if OpenDialog1.Execute then
  begin
    Edit1.Text := OpenDialog1.FileName;
  end;
end;
//==============================================================================
procedure TForm2.btnSelectBadFileClick(Sender: TObject);
begin
  if OpenDialog1.Execute() then
  begin
    Edit2.Text := OpenDialog1.FileName;
  end;
end;
//==============================================================================
procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  Application.Terminate;
end;

//==============================================================================
procedure TForm2.btnModifyClick(Sender: TObject);
var
  err : Boolean;
  i : integer;
  bArray: ByteArray;
  okFile, badFile : string;
begin
  okFile  := Edit1.Text;
  badFile := Edit2.Text;
  try
  if not FileExists(okFile) then
    ShowMessage('Please select working file!')
  else if not FileExists(badFile) then
    ShowMessage('Please select bad file!')
  finally
    err := False;
  end;
  try
    notCorrectFile(okFile, badFile, err);
    if err then
    Exit;
    read_(okFile, $FDFFF0, $1de, bArray);
    write_(badFile, $FDFFF0, bArray);
    lblAuthor.Visible := False;
    for i := 0 to 2 do
      begin
        Label1.Visible := True;
        application.ProcessMessages;
        sleep(400);
        Label1.Visible := False;
        application.ProcessMessages;
        sleep(400);
      end;
      lblAuthor.Visible := True;
      application.ProcessMessages;
      Sleep(1000);
      Application.Terminate;
    except
      ShowMessage('There''s been a problem!');
  end;
  end;
end.