IE8 Error in DataTables

O% with% below:

function _fnGetObjectDataFn( mSource )
    {
        if ( $.isPlainObject( mSource ) )
        {
            /* Build an object of get functions, and wrap them in a single call */
            var o = {};
            $.each( mSource, function (key, val) {
                if ( val ) {
                    o[key] = _fnGetObjectDataFn( val );
                }
            } );

Returns the following error:

  

1.10.4 jquery at line 1171 if ($ .isPlainObject (mSource))

How to solve it?