Is it a jquery 1.8.0 bug?I think it's about iframe and window.location

Is it a jquery 1.8.0 bug?I think it's about iframe and window.location

Hi guys.
I have 4 htmls using Jquery1.8.0 and easyui-tabs(it's a plugin BASE ON jquery).
1 html is "parent" and 3 are "children".
The parent one using easyui-tabs to generate 3 children tabs with js like belbow and each have an <iframe>.

the "parent" html 's javascript fragment.
<script type="text/javascript">
        window.onload = function () {
            $('#tt').tabs({
                border: true,
                width: $('#tt').parent().width(),
                height: $('#tt').parent().height()
            });
            $('#tt').tabs('add', {
                title: 'Create',
                id: 'iframe1',
                content: "<iframe width='100%' height='100%' frameborder='0' src='Order_CreateOrder.htm'></iframe>",
                closable: false
            });
            $('#tt').tabs('add', {
                title: 'Find',
                id: 'iframe2',
                content: "<iframe width='100%' height='100%' frameborder='0' src='Order_FindOrder.htm'></iframe>",
                closable: false
            });
            $('#tt').tabs('add', {
                title: 'Edit',
                id: 'iframe3',
                content: "<iframe  width='100%' id='t3' height='100%' frameborder='0' src='Order_EditOrder.htm'></iframe>",
                closable: false
            });
            $('#tt').tabs("select", "Create");
        }

I debug the htmls in a visual studio wetsite.
Here is my question:
some times I click an href try to locate to “the parent” html to see the 3 tabs,the visul studio alert a "Mircosoft Jscript runtime error"(about object invalid),the error code is located at "a.location" in the Jquery 1.8.0.min.js file.

This error is not all the time,so I think its maybe a bug in Jquery about multiple iframes(that means multiple "window"s)
Am I right?
AND CAN ANYBODY HELP TO SOLVE THIS PROBLEM PLEASE?
THANKS A LOT!