Server side filtering in dhtmlxgrid

Hello,

I am using dhtmlx grid with MVC in ASP.NET. I have applied everything according the the following tutorial
dhtmlx.com/blog/?p=1349

I need to do smart rendering also and filtering. I have done the smart rendering but when I try to filter in a column it shows error -
Microsoft JScript runtime error: ‘_locator’ is null or not an object — in the file dhtmlxgrid.js.

Pls help…

Unfortunately the issue cannot be reconstructed locally.
Please, provide any kind of sample of your code.