Nie działa zwijanie działu

wersja skryptu MyBB: 1.6.16
adres forum: http://gvs-p4s.cba.pl/index.php
na czym polega problem (screen, opis, komunikaty, nazwa stylu/theme/szablonu): Nie działa zwijanie działów, mój forumbit_depth1_cat

<div id="cat_{$forum['fid']}" class="content">
<div class="thead" id="th{$forum['fid']}">
<span class="forumtitle"><a href="{$forum_url}">{$forum['name']}</a></span><span class="forumdesc">{$forum['description']}</span>
<span class="expcolimage expcol_close"><img src="images/neonglow/collapse.gif" /></span>
<span class="expcolimage expcol_open"><img src="images/neonglow/collapse_collapsed.gif" /></span>
</div>
<div id="expcol_box{$forum['fid']}">
<table border="0" cellspacing="0" cellpadding="4" class="tborder tborder_2">
<tbody style="">
{$sub_forums}
</tbody>
</table>
</div>
<br />
</div>

oraz newfunctions.js :

$(document).ready(function () {

    var file_name, file_end, file_page, ucplink, dicon, ucpbox, sidebar, sidebarToggle, expopen, expclose, thead2, thead, thead_id, n, cookies, name, thnum, quoted, quoted_split;
    
    // Animated expand/collapse
    expopen = '.expcol_open';
    expclose = '.expcol_close';
    thead2 = '.thead_2';
    $(expclose).on("click", function () {
        thead = $(this).parent(thead2);
        thead_id = $(this).parent(thead2).attr("id");
        n = parseInt(thead_id.replace('th', ''), 10);
        $("#expcol_box" + n).slideUp();
        $(this).hide();
        thead.children(expopen).show();
        thead.animate({
            "border-radius": "5px",
            "opacity": "0.4"
        });
        $.cookie(n, "closed", {
            expires: 365
        });
        return false;
    });

    $(expopen).on("click", function () {
        thead = $(this).parent(thead2);
        thead_id = $(this).parent(thead2).attr("id");
        n = parseInt(thead_id.replace('th', ''), 10);
        $("#expcol_box" + n).slideDown();
        $(this).hide();
        thead.children(expclose).show();
        thead.animate({
            "border-radius": "5px",
            "opacity": "1"
        });
        $.cookie(n, "open", {
            expires: 365
        });
        return false;
    });

    // Restore collapses
    function get_cookies() {
        cookies = {};
        if (document.cookie && document.cookie !== '') {
            var split, i, name_value;
            split = document.cookie.split(';');
            for (i = 0; i < split.length; i += 1) {
                name_value = split[i].split("=");
                name_value[0] = name_value[0].replace(/^ /, '');
                cookies[decodeURIComponent(name_value[0])] = decodeURIComponent(name_value[1]);
            }
        }
        return cookies;
    }

    cookies = get_cookies();
    for (name in cookies) {
        if (cookies[name] === 'closed') {
            $("#expcol_box" + name).hide();
            thnum = $("#th" + name);
            thnum.css('opacity', '0.4');
            thnum.find('.expcol_open').show();
            thnum.find('.expcol_close').hide();
        }
    }

    // Multiquote fix
    if ($.cookie('multiquote') !== null) {
        quoted = $.cookie("multiquote");
        quoted_split = quoted.split('|');
        $.each(quoted_split, function () {
            $('#multiquote_link_' + this).addClass('multiquote_on');
        });
    }

    $('a.postbit_multiquote').click(function () {
        if ($(this).hasClass('multiquote_on')) {
            $(this).removeClass('multiquote_on');
        } else {
            $(this).addClass('multiquote_on');
        }
    });

});

Sprawdź:

<div id="cat_{$forum['fid']}" class="content">
<div class="thead{$expthead}" id="th{$forum['fid']}">
<div class="expcolimage"><img src="{$theme['imgdir']}/{$expcolimage}" id="cat_{$forum['fid']}_img" class="expander" alt="{$expaltext}" title="{$expaltext}" /></div>
<span class="forumtitle"><a href="{$forum_url}">{$forum['name']}</a></span><span class="forumdesc">{$forum['description']}</span>

</div>
<div id="expcol_box{$forum['fid']}">
<table border="0" cellspacing="0" cellpadding="4" class="tborder tborder_2">
<tbody style="{$expdisplay}" id="cat_{$forum['fid']}_e">
{$sub_forums}
</tbody>
</table>
</div>
<br />
</div>

Ponadto kilka kwestii odnośnie JS, headerinclude:

Bibliotekę jQuery przeniósłbym nieco niżej, tuż za includowane skrypty. Dodaj także jQuery.noConflict();.

Teraz tworzysz styl / przerabiasz, czy co tam robisz..., ale przemyślałbym nad wersją MyBB 1.8.x, gdzie już tego stylu na pewno nie użyjesz.
Czyż nie lepiej od razu na wyższej wersji pracować?