Unhandled Error!

Trying to get property of non-object

Document Post
Document type CMS page
Line 12
Exception class Cms_ExecutionException

Code Highlight

					<a href="<?php echo site_url('/'); ?>">Home</a>
				</li>
				<li>
					<a href="<?php echo site_url('/knowledge-base'); ?>">Knowledge Base</a>
				</li>
				<li>
					<a href="<?php echo site_url("/knowledge-base/post/$post->url_name"); ?>">
						<?
							$string = $post->title;
							// max 24 characters in title
							$string = (strlen($string) > 24) ? substr($string,0,24).'...' : $string;
						?>
						<?php echo $string; ?>
# Document Type
1 Post CMS page