JQuery: animate() doesn't work as expected in IE

function accordion_starting_page(){
    // hide all elements except the first one
    $('#FCE-Inhalt02-ContentWrapper .FCE-Fade:not(:first)').css("height", "0").hide();
    $('#FCE-Inhalt02-ContentWrapper .FCE-Fade:first').addClass("isVisible");

    $('div.FCE-Title').click(function(){

        // if user clicks on an already opened element => do nothing
        if (parseFloat($(this).next('.FCE-Fade').css("height")) > 0) {
            return false;
        }

        var toHide = $(this).siblings('.FCE-Fade.isVisible');

        toHide.removeClass("isVisible");

        // close all opened siblings
        toHide.animate({"height": "0", "display": "none"}, 1000);

        $(this).next('.FCE-Fade').addClass("isVisible").animate({"height" : "200"}, 1000);

        return false;
    });
}

$('li').hover(function(){

              $this = $(this);

              var bottom = '-45px'; //valor default para subir.

              if( $this.css('height') == '320px' ){bottom = '-115px';}

              $this.css('cursor', 'pointer').find('p').stop().find('.first').hide().end().animate({bottom: bottom}, {queue:false, duration:300});

      }, function(){

         var $this = $(this);

         var bottom = '-178px'; //valor default para descer

            if( $this.css('height') == '320px' ){bottom = '-432px';}

         $this.find('p').stop().animate({***position: 'absolute'***, bottom:bottom}, {queue:false, duration:300}).find('.first').show();

      });//fim do hover()

$('li').hover(function(){

                 $this = $(this);

         var bottom = '-45px'; //valor default para subir.

              if( $this.css('height') == '320px' ){bottom = '-115px';}

              $this.css('cursor', 'pointer').find('p').stop().find('.first').hide().end().animate({bottom: bottom}, {queue:false, duration:300});

      }, function(){

         var $this = $(this);

         var bottom = '-178px'; //valor default para descer

            if( $this.css('height') == '320px' ){bottom = '-432px';}

         $this.find('p').stop().animate({bottom:bottom}, {queue:false, duration:300}).find('.first').show();

      });//fim do hover()

$('#bs1').animate({
    "left": bs1x
}, 300, function() {
    // Animation complete.
});