jqueryerror "event has no properties", anyone help please?

Hi, got a small issue with running jquery in my drupal site, the "settings" section's not working, the General settings, Cache settings, File system settings etc are not appearing as links, so I can't update my settings. If I disable jquery, all is fine, so something's clashing with drupal's own js, and I can't figure out what it is. I ran through all the drupal misc/*.js and replaced $( with $id( as recommended, is there something else to look out for that I've missed?

Hope I've posted this in an appropriate group, quite new to Drupal and a first time new forum topic poster.

The JS error I get in my console is "event has no properties" at the "event.preventDefault" line in this routine:

		fix: function(event) {
			// check IE
			if(jQuery.browser.msie) {
				// get real event from window.event
				event = window.event;
				// fix target property
				event.target = event.srcElement;
			// check safari and if target is a textnode
			} else if(jQuery.browser.safari && event.target.nodeType == 3) {
				// target is readonly, clone the event object
				event = jQuery.extend({}, event);
				// get parentnode from textnode
				event.target = event.target.parentNode;
			}
			// fix preventDefault and stopPropagation
			event.preventDefault = function() {
				this.returnValue = false;
			};
			event.stopPropagation = function() {
				this.cancelBubble = true;
			};
			return event;
		}

I've not changed any of the js except as mentioned above afaik.