this.detachEvent(on+type,fn) bug in ie

Hello i am using the script belowm that works with mootools, when it runs on ie, it gives an error message. Tracked with ms debug, it brings up a mootools file with this part of the code as causing the error. i noticed there s some css in the body, i ll remove I checked and it s actullay not the problem

this.detachEvent(on+type,fn)

Code (markup):

here s the code i am using (an image gallery)

<?php
defined('_JEXEC') or die('Restricted access');
global $mainframe, $rsgConfig;
//Add stylesheets and scripts to header
$css1 = "<link rel=\"stylesheet\" href=\"components/com_rsgallery2/templates/slideshow_parth/css/jd.gallery.css\" type=\"text/css\" media=\"screen\" charset=\"utf-8\" />";
$mainframe->AddCustomHeadTag($css1);
$css2 = "<link rel=\"stylesheet\" href=\"components/com_rsgallery2/templates/slideshow_parth/css/template.css\" type=\"text/css\" media=\"screen\" charset=\"utf-8\" />";
$mainframe->AddCustomHeadTag($css2);
$css3 = "<link rel=\"stylesheet\" href=\"components/com_rsgallery2/templates/slideshow_parth/css/slimbox.css\" type=\"text/css\" media=\"screen\" charset=\"utf-8\" />";
$mainframe->AddCustomHeadTag($css3);

JHTML::_("behavior.mootools");

$js2 = "<script src=\"components/com_rsgallery2/templates/slideshow_parth/js/slimbox.js\" type=\"text/javascript\"></script>
<script src=\"components/com_rsgallery2/templates/slideshow_parth/js/jd.gallery.js\" type=\"text/javascript\"></script>
<script src=\"components/com_rsgallery2/templates/slideshow_parth/js/tip.js\" type=\"text/javascript\"></script>";
$mainframe->AddCustomHeadTag($js2);
?>
<!-- Override default CSS styles -->

<style>
#myGallery, #myGallerySet, #flickrGallery
{
	width: <?php echo $rsgConfig->get('image_width');?>px;
	
}
#thumbs{
	width: <?php echo $rsgConfig->get('image_width');?>px;
	position: relative;
	height: 135px;
	z-index: 15;
	margin: 0 auto;
	
}

/* Background color for the slideshow element */
.jdGallery .slideElement
{
	background-color: #edeced;
}

#tt {
 position:absolute;
 display:block;
 z-index:999;
 }
 #tttop {
 display:block;
 height:5px;
 margin-left:5px;
 overflow:hidden;
 }
 #ttcont {
 display:block;
 padding:2px 12px 3px 7px;
 margin-left:5px;
 background:#666;
 color:#fff;
 }
#ttbot {
display:block;
height:5px;
margin-left:5px;
overflow:hidden;
}

</style>
<script type="text/javascript">
	function startGallery() {
		var myGallery = new gallery($('myGallery'), {
					timed: false,
					useExternalCarousel: true,
					carouselElement: 'thumbs',
					showArrows: false,
					embedLinks: false,
					showCarouselLabel: false
					
					

		});
	}
	window.addEvent('domready',startGallery);
</script>
<div class="content">
	

	<div class="rsg2-clr"><br />
</div>
	<div id="myGallery">
		<?php echo $this->slides;?>
	</div><!-- end myGallery -->
	<div id="thumbs">
	</div>
</div><!-- End content -->

Code (markup):

tks to help