Twitter like slide panel sometimes didnt work

[samsons17]

Hi all.

I got some problem here.
I made a website using codeigniter framework.

And on my website there is the list of events that are happening at my university..
Whenever a person click on the events title bar, a slide panel like Twitter will shows up next to that particular event title..

The problem now is that, The slide panel is sometimes shows up, and sometimes did not.
I dont know whats the problem and really hope that you guys could help me out.

This is my website : www.inuevents.com

this is the ajax code in case you need it :

$('.title_row').live('click',function()
    {
        var id = $(this).attr('id');
        var data_id = $(this).find(".datahtml").val();
        var datas = $(this).find(".content").html();
        var panel= $('.panel');
        var panel_width=$('.panel').css('left');
        $("#panel-frame").css("display","block");

        if(data_id==id)
        {
            if(panel_width =='499px' && lastId!=data_id)
            {

            }
            else
            {
                panel.animate({
                    left: parseInt(panel.css('left'),0) == 0 ? +panel.outerWidth() : 0
                });
            }
            lastId = data_id;
        }
        var dataType = $(this).find(".imagelogo").css('height');

        var DATA = 'event_id=' + id;
        $.ajax({
            type: "POST",
            url: "<? echo site_url('[I]the class name and function name is here[/I]') ?>",
            data: DATA,
            cache: false,
            success: function(data){
            $(".panel").html(data);
             $('.close').click(function()
    {
        var panel= $('.panel');
        panel.animate({
            left: parseInt(panel.css('left'),0) == 0 ? +panel.outerWidth() : 0
        });
       // panel.html("");
        return false;
    });
            }
        });
        return false;

});

and this is the html code :

<div class="title_row" id="id">
                        <div class="content" >
                          <div class="data">
                            <div class="data_date">date</div>
                          <div class="data_title">Title</div>
                        </div>
                       </div><!--content ends here-->
</div><!--title row ends here-->

help me please...i really do not want to screw this project :(