I should also mention that prior to the error on line 336 I got the Explorer 8.0.6 error:
Line: 584
Object required jquery.smartmenus.js
which in my version of smart menus (0.93) is as follows starting at line 574
574: menuInit: function($ul) {
75: if (!ul.dataS('in-mega')) {
76: this.subMenus.push($ul);
77: // mark UL's in mega drop downs (if any) so we can neglect them
78: if ($ul.hasClass('mega-menu')) {
79: $ul.find('ul').dataSM('in-mega',true);
80: }
81: // get level (much faster than, for example, using parentsUtil)
82: var level = 2,
83: par = $ul[0];
584: while ((par = par.parentNode.parentNode) != this.$root[0]) {
85: level++;
86: }