Unhandled Error!

Trying to get property of non-object

Document	Category
Document type	CMS template
Line	64
Exception class	Cms_ExecutionException

Code Highlight

  <div id="topNav">
    <!--BEGIN MAIN NAV --><? $this->render_partial('lm_main_nav') ?><!--END MAIN NAV -->
  </div>
  <div id="content">
        <div id="nav_left_column">
          <div class="categories">
            <h2><?= $category->name ?></h2>
            <? $this->render_partial('shop:categories', array('parent_category'=>$category)) ?>
          </div>
          <div class="categories">
            <? $this->render_partial('shop:categories_brands') ?>
          </div>
                  </div>

#	Document	Type
1	Category	CMS template