[jQuery] jQuery(document).ready() Type error on WebKit based Browsers

[Sulfura]

Hi there,

I searched the internet for hours but couldn't find a solution which
worked for me. I use jQuery to call a Perl-Module which outputs an XML
File with all the Pictures in a specified Folder, which in turn is
interpreted by jQuery to show a preview of that same Folder.

It all works fine on Firefox, it works with some yet-unattended Bugs
on IE7, but on Safari and Opera (and all WebKit based Browsers for
that matter) it simply refuses to work. Both tell me that I have a
Type mismatch.

Code:
jQuery.noConflict();

jQuery(document).ready(function(){

    jQuery("#dir").change(function () {
       if (jQuery("input[name=mode]:checked").val() ==
"add_from_folder") {
            jQuery("#preview").hide();
            jQuery("select option:selected").each(function ()
{
              jQuery("#preview").empty();
                requestXML();
                jQuery("#preview").slideDown("slow");
           })
        }
    })
    .change();

    jQuery("input[name=mode]").change(function(){
        if (jQuery("input[name=mode]").val() == "add_blank") {
          jQuery("#preview").empty();
            jQuery("#preview").hide();
            jQuery("#dir").attr("value",";-;");
      } else {
            jQuery("#dir").attr("disabled", false);
        }
   })
    .change();

});

    function requestXML() {
        jQuery.ajax({
            type: "GET",
            url: "/cgi-bin/apps/load_preview?directory=" + jQuery
("#dir").val(),
            dataType: "xml",
            success: function(xml) {
                jQuery(xml).find("picture").each(function(){
                    jQuery("#preview").append("<img class='preview'
src='/" + jQuery(this).find("reference").text() + "' />")
                })
            }
        });
    }

##Code end

I know there are things that could be made more efficient but I am
still new to Ajax and jQuery and learned how to use it just yesterday,
so I accept any constructive criticism :)