Same content on differents tooltips

Hi, I'm going to bother you again, I promise this is the last time. When I insert differents tooltips on the same page, the content of the tooltip box is the same, whereas it should be different. 

Here is an exemple : http://www.ebookboost.fr/1.1.html 

(same content on the first two tooltip boxes, while the code is this : 

<span class="tooltip" onmouseover="tooltip.pop(this, '#demo2_tip')"><strong>querelle</strong> </span> 

<div style="display:none;">

    <div id="demo2_tip"> dispute</div>

</div> 

and this : 

<span class="tooltip" onmouseover="tooltip.pop(this, '#demo2_tip')"><strong>brebis</strong> </span> 

<div style="display:none;">

    <div id="demo2_tip">

        <img src="images/brebis.png" style="float:right;" />

    </div>

</div>)