Problem loading data from xml file

Hello,
I don´t know what is happening but I can´t load data in a AW.Table from a XML file.
This is what I´m trying
var tbl = new AW.XML.Table;
tbl.setURL("prueba.xml");
tbl.request();
alert(tbl.getCount());

Is simple, but not works, tbl.getCount() => return 0

My xml file contains this:

<?xml version="1.0" standalone="yes"?>
<NewDataSet>
<tabla>
<id>23</id>
<CodCli>1</CodCli>
<NomCli>Promopublic</NomCli>
<Telf>965896321</Telf>
</tabla>
<tabla>
<id>24</id>
<CodCli>2</CodCli>
<NomCli>Tecnora</NomCli>
<Telf>123456789</Telf>
</tabla>
<tabla>
<id>25</id>
<CodCli>3</CodCli>
<NomCli>Pabrama</NomCli>
<Telf>123456778</Telf>
</tabla>
<tabla>
<id>26</id>
<CodCli>4</CodCli>
<NomCli>Porttia Europea</NomCli>
<Telf>123666985</Telf>
</tabla>
<tabla>
<id>27</id>
<CodCli>5</CodCli>
<NomCli>GR - Asociados</NomCli>
<Telf>123654789</Telf>
</tabla>
</NewDataSet>

Already I have solved my problem, I was doing a thing badly.
Thank´s