jQuery Jquery Slideout Tab-panes that fail in IE

[m444w]

I am trying to have multiple divs with tabs that slide up, but only one can be activate at a time.

It works perfect in Chrome/FF, but in IE the tab animates up and down once (the div doesn't animate at all).

Which makes me think it has something to do with the bolded code.

This is the error message I get:

Message: Invalid argument.
Line: 144
Char: 219
Code: 0
URI: http://local.seagamfg.com/new/js/jquery-1.4.2.min.js


And here is my jquery code:

    $(document).ready(function() {
		$('#tabs > li').click( function() {
			if ($(this).hasClass("activetab")) {
                   
                    $('a', this).stop(true,true).animate({
                            'bottom'  :'0px',
							'z-index' :'100001'
                        }, 400, 'swing');
					$('div', this).stop(true,true).animate({
                            'marginBottom'  :'-400px',
							'z-index' :'100001'
                        }, 400, 'swing');
                  $(this).removeClass('activetab');
                
             } else {
			     $('#tabs').find('.activetab').each(function(){ 
				    
				     $('a, li', this).stop(true,true).animate({
                            'bottom'  :'0px',
			    'z-index' :'100001'
                        }, 400, 'swing');
			var child = (this).children('div');	
			$(child).stop(true,true).animate({
                            'marginBottom'  :'-400px',
			 'z-index' :'100001'
                        }, 400, 'swing');
                  $(this, 'li').removeClass('activetab'); 
				   })
				   
                   
		   $(this).addClass('activetab');
                    $('a', this).stop(true,true).animate({
                            'bottom'  :'400px',
			   'z-index' :'10000'
                        }, 400, 'swing'); 
					$('div', this).stop(true,true).animate({
                            'marginBottom'  :'0px',  
			   'z-index' :'10000'
                        }, 400, 'swing');
						
                               
                }
				
        })
		});

Nevermind... Apparently my pre-set z-index values must have gotten deleted while things were getting swapped around. For future reference for anyone that happens to read this thread, this failure in IE means that a value that you are trying to animate has not been defined.