[davidwu]

I've just fixed the problem with vBulltin staff's help. Please try this:

Edit navbar template, append this code to the end.

<!-- PAGENAV POPUP -->

    <div class="vbmenu_popup" id="pagenav_menu" style="display:none">
        <table cellpadding="4" cellspacing="1" border="0">
        <tr>
            <td class="thead" nowrap="nowrap">$vbphrase[go_to_page]</td>
        </tr>
        <tr>
            <td class="vbmenu_option" title="nohilite">
            <form action="$vboptions[forumhome].php" method="get" onsubmit="return this.gotopage()" id="pagenav_form">
                <input type="text" class="bginput" id="pagenav_itxt" style="font-size:11px" size="4" />
                <input type="button" class="button" id="pagenav_ibtn" value="$vbphrase[go]" />
            </form>
            </td>
        </tr>
        </table>
    </div>

<!-- / PAGENAV POPUP -->

It works for me. Good luck!