I know maybe this is not a common problem. But I can't show the row numbers. Here is the code (almost the same that you have in your examples page):

$grid = new jqGridRender($conn);
// Write the SQL Query
$grid->SelectCommand = 'SELECT tblgrupos.txtNombre Grupo, tbleventos.txtEvento txtEvento, tbleventos.dateFechaEvento dateFechaEvento, tbleventos.intPuntos intPuntos