Unhandled Error!

Trying to get property of non-object

Document Category
Document type CMS page
Line 4
Exception class Cms_ExecutionException

Code Highlight

<div id="cat-page" style="width:100%;">
	<script type="text/javascript">
		jQuery(document).ready(function($){
			cur_men = '<?= $category->url_name;?>';
			$('#left-nav li').each(function(){
				if($(this).attr('id') == cur_men) {
					$(this).addClass('current');
				}
			});
			$('#left-nav li.current').parents('ul').show();
			$('#left-nav li').has('ul').addClass('haschild');
			$('#left-nav li.current').parent('ul').parent('li').addClass('open');
			/*if($('#left-nav li li').has('ul').length){
# Document Type
1 Category CMS page