Unhandled Error!

Trying to get property of non-object

Document	product
Document type	CMS page
Line	2
Exception class	Cms_ExecutionException

Code Highlight

<? 
  if ($product->category_list[0]->name === "Collection") {
   $this->render_partial('size_select');
  }
?>
<div id="item">
<div class="demo">
<div id="main_image"></div>
<ul class="gallery_demo_unstyled">
  <? $i = 0; ?>
      <? foreach ($product->images as $image): ?>
  <? if ($i == 0) { $active = " class='active'"; } else { $active = ''; } ?>
  <li<?= $active ?>><img src="<?= $image->getThumbnailPath('auto','auto') ?>" /></li>

#	Document	Type
1	product	CMS page