'dhtmlXGridObject' is undefined

I have the following jsp page, i need to load it into an html iframe. After loading the page i get a “‘dhtmlXGridObject’ is undefined” error, this happens at the following line:

mygrid = new dhtmlXGridObject('gridbox');

and this is the page:

[code]

<div id="gridbox" style="overflow:hidden;width:100%;height:100%"></div>    


<!-- RECOMMENDED if your web app will not function without JavaScript enabled -->
<noscript>
	<div
		style="width: 22em; position: absolute; left: 50%; margin-left: -11em; color: red; background-color: white; border: 1px solid red; padding: 4px; font-family: sans-serif">
		Your web browser must have JavaScript enabled in order for this
		application to display correctly.</div>
</noscript>
[/code]

thanks in advance

Please, make sure that the js sources of the dhtmlx are loaded successfully on the page.
If the problem still occurs for you pleas,e share with a demo link, where the problem can be reconstructed.