[Solved] grid refresh doesn't work with json2

[Cristiano]

I'm using

Html.Telerik().Grid.... as per CheckBoxesAjax.cshtml sample

If I include json2.js library (I need to serilize custom js obj using JSON.stringify)
telerik grid refresh button throws at json2.js line 191

        String.prototype.toJSON      =
            Number.prototype.toJSON  =
            Boolean.prototype.toJSON = function (key) {
                return this.valueOf();//line 191
            };

[Fleish]

I have same problem,
It occurs in ie7 only, in ie8/9/firefox/chrome it works fine.
Did you solve it?
If not, somebody else, pls!