Jquery Expander Widget

Yii 1.1 Extensions
1

Hi, I am trying to use Jquery expander widget, I write


<?php

				$this->widget('ext.expander.Expander',array(

		            'content'=>$data->incidencia_descripcion,

		            'config'=>array('slicePoint'=>10, 'expandText'=>'Leer más', 'userCollapseText'=>'Ocultar', 'preserveWords'=>false)

		        ));

			?>

But display an error 500, telling that expander.php is not an existing file. Anyone know why is this happening?


Error 500: <h1>CException</h1>

<p>Alias "ext.expander.Expander" is invalid. Make sure it points to an existing PHP file and the file is readable. (/Applications/XAMPP/xamppfiles/htdocs/yii/framework/YiiBase.php:322)</p>