[jQuery] Button doesn't work in jquery dialog

[Sara]

Hi everybody

I have a jquery dialog which loads an .aspx page and this  page
contains only a label and button controls
the dialog opens and loads the page fine but when button click of that
page has not been fired at all and generates the following javascript
error:

'theForm.__EVENTTARGET' is null or not an object

my code:
jQuery(document).ready(function(){

      jQuery("#Button1").click(function(){
           jQuery("#myDiv").dialog({ modal: true, overlay: { opacity:
0.5, background: "black" },title: "Install Module" ,resizable:
false,show: "slow",width: "300px",height: "300px" });
           jQuery("#myDiv").load("Default3.aspx").dialog("open");

      });
    });

please help me
thanks