This may be because of a DUPLICATION of the call to display attributes in your tpl_product_info_display.php file .
This file will reside in your TEMPLATES folder.
(Look at the PAGE SOURCE html of the page in question. You'll see the following HTML - which suggests such a duplication as I describe)
HTML Code:
<!--bof Attributes Module -->
<div id="col3">
<div id="productAttributes">
<div class="wrapperAttribsOptions">
<h4 class="optionName back">Bite</h4>
<div class="back">
<input type="radio" name="id[13]" value="21" checked="checked" id="attrib-13-21" /><label class="attribsRadioButton one" for="attrib-13-21"><img src="images/attributes/attribute_bites.gif" alt="" width="166" height="31" /> ( $18.00 )</label><br />
</div>
<br class="clearBoth" />
</div>
<br class="clearBoth" />
<div class="wrapperAttribsOptions">
<h4 class="optionName back">Classic</h4>
<div class="back">
<input type="radio" name="id[14]" value="22" checked="checked" id="attrib-14-22" /><label class="attribsRadioButton one" for="attrib-14-22"><img src="images/attributes/attribute_classic.gif" alt="" width="166" height="29" /> ( $30.00 )</label><br />
</div>
<br class="clearBoth" />
</div>