[Lazarus] How to use TPrintDialog

[tim launchbury]

Hello all

I am trying to implement printing in my app and want to use the
printdialog included with lazarus. I have dropped the print dialog on
the form and set it to appear when a button is clicked.

When the printdialog.execute function is executed an exception is
generated. The exception is 
"Project raised exception class 'EReadError' with message:
Unknown property :"Caption""

This is followed by

"Project raised exception class 'EReadError' with message:
Error reading pgCopies.Caption: Unknown property :"Caption""

I have tried all the suggestions I could found on the wiki and the
delphi site. 

my code is as follows:

unit Unit1; 

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
StdCtrls, Printers, PrintersDlgs;

type

  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    PrintDialog1: TPrintDialog;
    procedure Button1Click(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end; 

var
  Form1: TForm1; 

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.Button1Click(Sender: TObject);
begin
  if printdialog1.execute then
  begin
    writeln(' ');
  end;
end;

end.
            
This problem occurrs with lazarus 0.9.29 revision 28950 and fpc 2.4.0
in linux with gtk2

Any suggestions or corrections would be gratefully
received.

Tim