treeGrid error

Hi,

When I tried to show the treegrid on ff I get this error "z is undefined
else var ind=z.childs.length; "

    gridCuenta = dhxLayout.cells("a").attachGrid();  
gridCuenta.imgURL = "img/dhtmlxGrid/icons_greenfolders/";
gridCuenta.setColAlign("center,center,center");
gridCuenta.setColTypes("tree,ro,ro");
gridCuenta.setColSorting("str,str,str");	
gridCuenta.init();	
gridCuenta.setSkin("dhx_skyblue");	
gridCuenta.loadXMLString(info);	

info = ‘’+
‘’+
‘Cuenta’+
‘ESN’+
‘Tipo’+
‘’+
‘’+
‘Cuenta2’+
‘ESN2’+
‘Tipo2’+
‘’+
‘’;

can you help me to fix the problem??

Thanks!!

Try to remove ‘parent=“h0”’