Problem Plugin Vanilla 2.5

Hi, I have a plugin works fine 2.3.1, but in 2.5 it does not work,

Folder:

Widget:
    module:
        class.dolartodaymodule.php

Error:

Class 'DolartodayModule' not found

The error occurred on or near: /public_html/plugins/Widgets/default.php

57: //var_dump($item);

58: // do the permission check with "Plugins.Whatever.{$moduleName}.View"

59: // attach module with $module = new $modules$moduleName;

60: if ($session->CheckPermission('Plugins.Widgets.' . $item . '.View')) {

61: $module = new $modules$item;

62: $sender->addModule($module);

63: }

64: }

65: }

Define class.dolartodaymodule.php:

class DolartodayModule extends Gdn_Module {
}

Thks,