superfish javascript error

My site is https://www.rockandrollwritein.com.

Using IE8, I get the following error:

Message: Object doesn’t support this property or method
Line: 123
Char: 2
Code: 0
URI: https://rockandrollwritein.com/wp-content/themes/themorningafter/includes/js/superfish.js?ver=3.0.1

Here is the code in question. Do you see the error?

/*
 * Superfish v1.4.8 - jQuery menu widget
 * Copyright (c) 2008 Joel Birch
 *
 * Dual licensed under the MIT and GPL licenses:
 * 	https://www.opensource.org/licenses/mit-license.php
 * 	https://www.gnu.org/licenses/gpl.html
 *
 * CHANGELOG: https://users.tpg.com.au/j_birch/plugins/superfish/changelog.txt
 */

;(function($){
	$.fn.superfish = function(op){

		var sf = $.fn.superfish,
			c = sf.c,
			$arrow = $(['<span class="',c.arrowClass,'"> »</span>'].join('')),
			over = function(){
				var $$ = $(this), menu = getMenu($$);
				clearTimeout(menu.sfTimer);
				$$.showSuperfishUl().siblings().hideSuperfishUl();
			},
			out = function(){
				var $$ = $(this), menu = getMenu($$), o = sf.op;
				clearTimeout(menu.sfTimer);
				menu.sfTimer=setTimeout(function(){
					o.retainPath=($.inArray($$[0],o.$path)>-1);
					$$.hideSuperfishUl();
					if (o.$path.length && $$.parents(['li.',o.hoverClass].join('')).length<1){over.call(o.$path);}
				},o.delay);
			},
			getMenu = function($menu){
				var menu = $menu.parents(['ul.',c.menuClass,':first'].join(''))[0];
				sf.op = sf.o[menu.serial];
				return menu;
			},
			addArrow = function($a){ $a.addClass(c.anchorClass).append($arrow.clone()); };

		return this.each(function() {
			var s = this.serial = sf.o.length;
			var o = $.extend({},sf.defaults,op);
			o.$path = $('li.'+o.pathClass,this).slice(0,o.pathLevels).each(function(){
				$(this).addClass([o.hoverClass,c.bcClass].join(' '))
					.filter('li:has(ul)').removeClass(o.pathClass);
			});
			sf.o[s] = sf.op = o;

			$('li:has(ul)',this)[($.fn.hoverIntent && !o.disableHI) ? 'hoverIntent' : 'hover'](over,out).each(function() {
				if (o.autoArrows) addArrow( $('>a:first-child',this) );
			})
			.not('.'+c.bcClass)
				.hideSuperfishUl();

			var $a = $('a',this);
			$a.each(function(i){
				var $li = $a.eq(i).parents('li');
				$a.eq(i).focus(function(){over.call($li);}).blur(function(){out.call($li);});
			});
			o.onInit.call(this);

		}).each(function() {
			var menuClasses = [c.menuClass];
			if (sf.op.dropShadows  && !($.browser.msie && $.browser.version < 7)) menuClasses.push(c.shadowClass);
			$(this).addClass(menuClasses.join(' '));
		});
	};

	var sf = $.fn.superfish;
	sf.o = [];
	sf.op = {};
	sf.IE7fix = function(){
		var o = sf.op;
		if ($.browser.msie && $.browser.version > 6 && o.dropShadows && o.animation.opacity!=undefined)
			this.toggleClass(sf.c.shadowClass+'-off');
		};
	sf.c = {
		bcClass     : 'sf-breadcrumb',
		menuClass   : 'sf-js-enabled',
		anchorClass : 'sf-with-ul',
		arrowClass  : 'sf-sub-indicator',
		shadowClass : 'sf-shadow'
	};
	sf.defaults = {
		hoverClass	: 'sfHover',
		pathClass	: 'overideThisToUse',
		pathLevels	: 1,
		delay		: 800,
		animation	: {opacity:'show',height:'show'},
		speed		: 'normal',
		autoArrows	: true,
		dropShadows : false,
		disableHI	: false,		// true disables hoverIntent detection
		onInit		: function(){}, // callback functions
		onBeforeShow: function(){},
		onShow		: function(){},
		onHide		: function(){}
	};
	$.fn.extend({
		hideSuperfishUl : function(){
			var o = sf.op,
				not = (o.retainPath===true) ? o.$path : '';
			o.retainPath = false;
			var $ul = $(['li.',o.hoverClass].join(''),this).add(this).not(not).removeClass(o.hoverClass)
					.find('>ul').hide().css('visibility','hidden');
			o.onHide.call($ul);
			return this;
		},
		showSuperfishUl : function(){
			var o = sf.op,
				sh = sf.c.shadowClass+'-off',
				$ul = this.addClass(o.hoverClass)
					.find('>ul:hidden').css('visibility','visible');
			sf.IE7fix.call($ul);
			o.onBeforeShow.call($ul);
			$ul.animate(o.animation,o.speed,function(){ sf.IE7fix.call($ul); o.onShow.call($ul); });
			return this;
		}
	});

})(jQuery);

jQuery(document).ready(function() {
	jQuery('ul#main-nav').superfish();
});