Q:

magento loads catalog/product/view.phtml twice

I am trying to create a magento side bar box that can list products in certain category.
I have created a file that creates a list of products in a certain catagory called most_sold_list.phtml with the following contents...
    <?php
        $_productCollection_1 = $this->getLoadedProductCollection();
    ?>
    <div class="link_list_with_title">
        <p class="catagory_title">Best Sellers</p>

        <ul>
        <?php foreach ($_productCollection_1 as $_product_1): ?>
            <li>
                <a href="<?php echo $_product_1->getProductUrl() ?>" title="<?php echo $_product_1->getName(); ?>"><?php echo $_product_1->getName(); ?></a>
            </li>
        <?php endforeach ?>
        </ul>
    </div>

I then update my local.xml to contain (within <default><reference name="left">)...
    <block type="catalog/product_list" name="most_sold.leftnav" template="most_sold_list.phtml">
        <action method="setCategoryId"><category_id>18</category_id></action>
    </block>            

This add the block to the page as I would expect. But when I go to the products page I get the following error...
Fatal error: Cannot redeclare get_quatity_weight_string_view() (previously declared in /.../app/design/frontend/superchef/default/template/catalog/product/view.phtml:37) in /.../app/design/frontend/superchef/default/template/catalog/product/view.phtml on line 54

I have checked and that function is not declared anywhere else and this error message goes away as soon as I remove my new block. Also note line 54 is the closing brace of the function.
I have tried removing that function completely by putting its code inline but then I just get the magento error message page.
The only conclusion I can come to is that view.phtml is being loaded twice. I have searched for this and I have seen mentions of zend loader loading files twice.
Can anybody help me fix this, it makes no sense to me.

A:

I have now worked out how to solve this problem from reading this:
http://www.bwigg.com/2010/01/magento-featured-products-in-sidebar/
So here is what I have done incase anybody else hits this weird problem.
update the layout xml file so the block type is "catalog/navigation".
So it now looks like this...
<block type="catalog/navigation" name="most_sold.leftnav" template="most_sold_list.phtml">
            <action method="setCategoryId"><category_id>18</category_id></action>
 </block>

