lennartrip on "Spam Link"

Hey there,

I'm having a problem with one of my wordpress sites.
When I view my pages while I am logged in as admin nothing is wrong.
However, when I am viewing my pages while I'm not logged in as admin something strange happens: a spam link is added near the footer.
This is the page HTML source when I am not in admin mode:

<a href="http://techetheatre.org" style="color#333; font-size:0.8em;">happy wheels</a>
        <div class="pagenumbers">
                </div>

    </div>
    </article>
</div></div>
    </div>
</section>    

            <!-- footer -->
        <footer id="colophon" role="contentinfo" data-role="footer" data-position="fixed" data-fullscreen="true">
            <div class="row   row_id_delimiter123 "><div class="delimiter  twelve columns"><div style="border-top: 1px dotted #cecece;" class="delimiter-type pointed margin_30px "></div></div></div><div class="row element row_id_copyright "><div class="copyright align-left six columns">            <p class="copyright">Copyright © 2013 <a href="http://annekezuidema.nl" target="_blank">Anneke Zuidema</a>. Alle rechten voorbehouden.</p>
        </div><div class="socialicons align-right six columns">
        <ul class="cosmo-social align-top">

The <a href="http://techetheatre.org" style="color#333; font-size:0.8em;">happy wheels</a> code is not in the source HTML of the page when I am logged in as admin.

I have no clue how to resolve this problem, I want to remove the link, I have checked all template files, CSS files, PHP files and searched for 'happy wheels' but it didn't find anything.
How can I fix this? I will make a donation to the person that can help me solve this.

EDIT: This is the link to the page http://www.annekezuidema.nl/?page_id=340 scroll all the way down and you will see a link to 'happy wheels'. This is what needs to be removed.