Прога на ХР работает, а на Windows 7 не хочет. Что делать??

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs,  ImageHlp, StdCtrls;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    Label1: TLabel;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
function PathAbsolute(path: string):string;
 var
  buff: array [0 .. $FF] of Ansichar;
begin
  if (path[1]=path[length(path)]) and (path[1]='%') then begin
    ExpandEnvironmentStrings(PAnsiChar(AnsiString(path)), buff, SizeOf(buff));
    Result := buff;
  end else
    result:=path;
end;
 
function SearchForFile(const ARootPath, AFileName: string;  var APathFound: string): Boolean;
var
   Found: array[0..500] of AnsiChar;
begin
   FillChar(Found, SizeOf(Found), #0 );
   Result := (SearchTreeForFile(PAnsiChar(PathAbsolute(ARootPath)), PAnsiChar(AFileName), Found) = True);
   APathFound := ExtractFilePath(Found);
end;
 
procedure TForm1.Button1Click(Sender: TObject);
var
   APathFound: string;
   begin
   if SearchForFile('%appdata%', 'test.txt', APathFound) then
   label1.caption:=('файл найден в ' + APathFound);
 
end;
 
 
end.