Error with Tag Widget

I've tried Firebugging it. 

it says I have to post again, the response in Firebug is then:

var $j = jQuery.noConflict();

	// If we haven't yet got the function

	if 	(typeof(TagCompleter) != 'function') {

		function TagCompleter(tagEntryField, tagIndicatorList, delimiter) {



			var theEntry = $j('#'+tagEntryField);

			var theList = $j('#'+tagIndicatorList);



			// Make sure the elements that have been supplied exist

			if (!theEntry.length) {

				return;

			}



			// Attach events

			// Add hilights every time the tag field changes

			$j(theEntry).change(function(e) { addHilights(); });



			// Add tag every click on a tag in the list

			$j('#'+tagIndicatorList + ' li').click( function(e) { addTag(e); } );



			// Get an array of the current tags in the field

			var getTags = function() {

				// Get the contents of the field

				// Split is by commas

				// Trim each item of whitespace at the beginning and end

				var theTags = $j(theEntry).val().split(delimiter);

				$j.each(theTags, function(i,v) {

					theTags[i] = $j.trim(v);

						if (theTags[i] == '') {theTags.splice(i, 1); } // Remove any empty values

					});

				return theTags;

			};



			// Add the tag that has been clicked to the field

			var addTag = function (e) {

				var newTag = $j.trim($j(e.target).text());

				var oldTags = getTags();



				// Mark the document as dirty for Modx by triggering a "change" event

				$j(theEntry).trigger("change");



				// Is the tag already in the list? If so, remove it

				var thePos = $j.inArray(newTag, oldTags);

				var tagSpacer = (delimiter == ' ') ? '': ' ';

				if (thePos != -1) {

					oldTags.splice(thePos, 1);

					$j(theEntry).val(oldTags.join(delimiter+tagSpacer));

				} else { // Not in the list, so add it

					oldTags.push(newTag);

					$j(theEntry).val(oldTags.join(delimiter+tagSpacer));

				}

				addHilights();

			};



			// Highlight any tags in the tag list which are already in the field

			var addHilights = function() {



				var tagsInField = getTags();



				$j('#'+tagIndicatorList + ' li').each( function() {

					if ($j.inArray($j.trim($j(this).text()) , tagsInField) != -1) {

						$j(this).addClass('tagSelected');

					} else {

						$j(this).removeClass('tagSelected');