FindNextFile

[Error] Unit1.pas(69): Types of actual and formal var parameters must be identical

procedure TForm1.btnAlterarClick(Sender: TObject);
var
   path,filename : String;
   achou : boolean;
begin
   try
     achou := True;
     path := ExtractFilePath(cmbPath.Filename);
     filename := ExtractFileName(cmbPath.Filename);
     if achou then
        while achou do
        begin
           if FileExists(path + filename) then
           begin
              RenameFile(path + filename, ´1´ + copy(filename,2,Length(filename)));
              FindNextFile(1,1);
              filename := ExtractFileName(cmbPath.Filename);
           end
           else
              achou := False;
        end;
   finally
      Application.MessageBox(´Arquivos Renomeados com Sucesso !!!´,
                             ´´, MB_ICONASTERISK + MB_OK);
      btnNovoClick(Sender);
   end;
end;