unbegründete AccessViolation?

[Muetze1]

Delphi-Quellcode:

procedure TMyArtz.Delete1Click(Sender: TObject);
var 
  i, w, h : Integer;
  lElem: TPaintBox;
begin
  If ( tabs.ActivePageIndex > -1 ) Then
  Begin
    lElem := FindComponent('pb_' + IntToStr(tabs.ActivePageIndex)) As TPaintBox;

    If Assigned(lElem) Then
    Begin
      w := lElem.width;
      h := lElem.height;

      lElem.Canvas.Rectangle(0,0,w,h);
    End;
  End;
end;