Stack Überlauf, beim eruezgen der eigenen Klasse! Wieso??

[SimStar001]

Hallo, ich habe folgende Klasse deklariert:

Delphi-Quellcode:

unit Livetrack;

interface

uses IdFTP, IdHTTP;

type TFTP = class(TIDFTP)
    end;

type THTTP = class(TIDHTTP)
    end;

type TLivetrack = class(TObject)
      private
      {private Vars}
      FHTTP : THTTP;
      FFTP : TFTP;
      FCacheDirectory : string;
      FFTPHost : String;
      FFTPDirectory : String;
      FFTPLoginName : String;
      FFTPPassword : String;
      FHTTPUrl : String;
      FFileName : String;
      FVID : String;

      {Set Procedures}
      procedure SetFTPHost(Host : String);
      procedure SetFTPDirectory(Directory : String);
      procedure SetFTPLoginName(LoginName : String);
      procedure SetFTPPassword(Password : String);
      procedure SetVID(VID : String);

      {get Functions}
      function GetFTPHost : String;
      function GetFTPLoginName : String;
      function GetFTPPassword : String;

      public
      {Functions}
      constructor create(const CacheDirectory : String; const FTPHost : string; const FTPDirectory : string; const FTPLoginName : string; const FTPPassword : string; const HTTPUrl : String; const FileName : String; const VID : string); overload;
      constructor create(const CacheDirectory : String; const FTPHost : string; const FTPDirectory : string; const FTPLoginName : string; const FTPPassword : string; const HTTPUrl : String; const FileName : String); overload;
      destructor destroy ; override;

      {properties}
      property CacheDirectory : String read FCacheDirectory write FCacheDirectory;
      property FTPHost : String read GetFTPHost write SetFTPHost;
      property FTPDirectory : String read FFTPDirectory write SetFTPDirectory;
      property FTPLoginName : String read GetFTPLoginName write SetFTPLoginName;
      property FTPPassword : String read GetFTPPassword write SetFTPPassword;
      property HTTPUrl : String read FHTTPUrl write FHTTPUrl;
      property FileName : String read FFileName write FFileName;
      property VID : String read FVID write SetVID;
      end;

implementation

{Set Procedures}

procedure TLivetrack.SetFTPHost(Host : String);
begin
  self.FFTP.Host := Host;
end;

procedure TLivetrack.SetFTPDirectory(Directory : String);
begin
  if Directory = '' then
    exit;
    
  if self.FFTP.Connected then
    self.FFTP.ChangeDir(Directory);
end;

procedure TLivetrack.SetFTPLoginName(LoginName : String);
begin
  if  self.FFTP.Connected then
    exit;

  self.FFTP.Username := LoginName;
end;

procedure TLivetrack.SetFTPPassword(Password : String);
begin
  if self.FFTP.Connected then
    exit;

  self.FFTP.Password := Password;
end;

procedure TLivetrack.SetVID(VID : String);
begin
  self.VID := VID;
end;
// Ende Set Procedures

////////////////////////////////////////////////////////////////////////////////


{Get Functions}

function TLivetrack.GetFTPHost : String;
begin
  result := self.FFTP.Host;
end;

function TLivetrack.GetFTPLoginName : String;
begin
  result := self.FFTP.Username;
end;

function TLivetrack.GetFTPPassword : String;
begin
  result := self.FFTP.Password;
end;
// Ende Get Functions

////////////////////////////////////////////////////////////////////////////////


{Constructor}

constructor TLivetrack.create(const CacheDirectory : String; const FTPHost : string; const FTPDirectory : string; const FTPLoginName : string; const FTPPassword : string; const HTTPUrl : String; const FileName : String);
begin
  inherited create;

  self.FFTP := TFTP.Create(nil);
  self.FHTTP := THTTP.Create(nil);

  // Setzen der Parameter für HTTP und FTP
  self.CacheDirectory := CacheDirectory;
  self.FTPHost := FTPHost;
  self.FTPDirectory := FTPDirectory;
  self.FTPLoginName := FTPLoginName;
  self.FTPPassword := FTPPassword;
  self.HTTPUrl := HTTPUrl;
  self.FileName := FileName;
  //self.VID := 'none';

end;

constructor TLivetrack.create(const CacheDirectory : String; const FTPHost : string; const FTPDirectory : string; const FTPLoginName : string; const FTPPassword : string; const HTTPUrl : String; const FileName : String; const VID : string); 
begin
  inherited create;

  self.FFTP := TFTP.Create(nil);
  self.FHTTP := THTTP.Create(nil);

  // Setzen der Parameter für HTTP und FTP
  self.CacheDirectory := CacheDirectory;
  self.FTPHost := FTPHost;
  self.FTPDirectory := FTPDirectory;
  self.FTPLoginName := FTPLoginName;
  self.FTPPassword := FTPPassword;
  self.HTTPUrl := HTTPUrl;
  self.FileName := FileName;
  //self.VID := VID;

end;
// Ende Constructor

////////////////////////////////////////////////////////////////////////////////


{Destructor}

destructor TLivetrack.destroy;
begin
  self.FFTP.Free;
  self.FHTTP.free;

  inherited destroy;
end;
// Ende Destructor

////////////////////////////////////////////////////////////////////////////////

end.

Nun habe ich das Problem, dass es zu einem Stack Überlauf kommt wenn ich diese erzeugen will, allerdings nur wenn ich die Property VID aufrufe.

property VID : String read FVID write SetVID;
Der Aufruf sieht so aus :

Delphi-Quellcode:

type TForm1 = class(TForm)
   (...)
   public
    Livetrack : TLivetrack;
    { Public-Deklarationen }
  end;

(...)

Livetrack := TLivetrack.create(extractfilepath(paramstr(0)) + '\Data\Cache','marcos-ivao-tools.net'
  ,'***','***','***','***','data.csv');

Hat wer ne Idee, wieso es gerade beim Aufrufen von VID zum Überlauf kommt?