I have an problem to get my jQuery code working with D7...in HTML it works fine but with D7 it doesnt work at all...

the code:

(function ($) {

  Drupal.behaviors.exampleModule = {
    attach: function(context, settings) {							
				
		var thumbstart = $("ul li img");		
		
		for (var i = 0, ii = thumbstart.length; i < ii; i++){
			if (thumbstart[i].title && thumbstart[i].title.length > 0)
			{			
				var imgtitle = thumbstart[i].title;		
				$(thumbstart[i]).wrap('<div class="wrapper" />').				
				after('<div class=\'inner\'><span class=\'caption\'>' + imgtitle + '</span></div>').
				removeAttr('title');
											
			}					
		};
	// At here the code works fine...
	$('.wrapper').find('img').css({opacity: ".8"}); 
	$('.teaser').find('.caption').css({top:"107px"}); 
	$('.test2').find('.caption').css({top:"165px"}); 
				
	$('.teaser').hover(
		function(){
			$(this).find('img').animate({opacity: "1.0"}, 300);		
			$(this).find('.caption').animate({top:"160px"}, 300);				
		}, 
		function(){
			$(this).find('img').animate({opacity: ".8"}, 300);	
			$(this).find('.caption').animate({top:"107px"}, 300);			
		}		
		);	
		

    }
  };

})(jQuery);

the problem is that the top of part is not working (begins at: var thumbstart...) is there anything that i can do? Does D7 need extra librarys/modules?