Klasse erzeugen_access Violation ...WARUM??

[silex carmen]

was habe ich wieder falsch gemacht! Ich bekomme ständig ein Access Violation Fehler!!
<br>
<pre>
unit PCIDSK;

interface

uses Sysutils,classes;

type TPix = class(TObject)
id:array[0..63] of char;
function getid:string;
constructor createPix(pix:string) ;
end;
implementation

constructor TPix.createPix(pix:string);
var
pixfile:TStream;
begin
inherited Create;
pixfile:=Tfilestream.Create(pix,fmOpenRead);
pixfile.Position:=49;
pixfile.Read(id,sizeof(id));
pixfile.free;
end;

function TPix.getid:string;
begin
result:=id;
end;

end.

</pre>

[Jörg Prepadnik]

Bei mir gehts:<BR>
<BR>
<PRE>
unit unTest;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, AStdBtn;

type
TPix = class(TObject)
id: array[0..63] of char;
function GetId: string;
constructor CreatePix(Pix: String);
end;

TForm1 = class(TForm)
AStdBtn1: TAStdBtn;
procedure AStdBtn1Click(Sender: TObject);
procedure FormActivate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
objPix: TPix;
public
{ Public-Deklarationen }
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

{ TPix }

constructor TPix.CreatePix(Pix: String);
var
PixFile: TStream;
begin
inherited Create;
Pixfile := TFileStream.Create(Pix, fmOpenRead);
Pixfile.Position := 49;
Pixfile.Read(Id, SizeOf(Id));
Pixfile.Free;
end;

function TPix.GetId: string;
begin
Result := Id;
end;

procedure TForm1.AStdBtn1Click(Sender: TObject);
begin
objPix.CreatePix('unTest.pas');
AStdBtn1.Caption := objPix.GetId;
end;

procedure TForm1.FormActivate(Sender: TObject);
begin
objPix := TPix.Create;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
objPix.Free;
end;

end.
</PRE&gt