[jQuery] JQuery error load data in dialog

[dEwA nich]

dear friends,

I have one input field, when I write some letter and press enter then ajax
request will happen. Return value from ajax I append to one tag div. Then I
load data into dialog. I can do that, but the problem is It just happens one
time and the problem when data successfully load, the close button of the
dialog doesn't work fine. Do I have something wrong??

this is my example code :
$("#dialog").dialog({
            bgiframe: true,
            autoOpen: false,
            height: 900,
            width:800,
            modal: true,
            buttons: {
                'Tutup': function() {
                    $(this).dialog('close');
                },
                'Simpan' : function() {
                    $('form#saveform').submit();
                }
            }
        });

$('.textfield').keypress(function(event){
            if (event.which == 13) {
                var z = $(this).attr('id');
                var nilai = $('#'+z).val();
                $('#nick').val(nilai);

                $('#fpersonform').submit();
            }

        });

$('#personform').submit(function() {

            $.ajax({
                type    : "POST",
                url        : some_url,
                data    : 'name=' + $('#nick').val(),
                success    : function(data) {

                    $('#dialog').dialog('open');
                    $('#dialog').html(data);
                }
            })
            return false;
        });