[StarBuG]

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<div id="thread_controls" class="thread_controls

I think the "toolsmenu" part was added in later Versions.

or as alternative search for this code and put my code below it:

<div id="pagetitle" class="pagetitle">
    <h1>
        {vb:rawphrase thread}: <span class="threadtitle"><a href="{vb:raw thread_url}" title="{vb:rawphrase reload_this_page}">{vb:raw threadinfo.title}</a></span>
        <vb:if condition="$show['fb_likebutton']">
            {vb:raw fblikebutton}
        </vb:if>
    </h1>
</div>

However you should really upgrade your vBulletin because there are tons of bugfixes since 4.0.4