[jQuery] ie 7 and 8 not rendering animation

anybody ever run into a problem where animation doesn't render? weird
thing is, it works just fine in ie6.

the animation actually runs, i've thrown some alerts in there to make
sure it works, but the animation itself does not render. and it's
only in a modal, all other animations on the page render fine
(including the same kind of slides i am doing here)

here's the offending code:

BH.Modal.openMe = function(mc){
$('#get_nav').add('#share_nav').removeClass('selected');
$('#greyBox').css({'width':'100%', 'height':$(document).height() +
'px', 'display':'inline-block'});
$('#modal').css({'display':'inline-block', 'top': ($(window).height
() / 2) - 260 + 'px', 'left': ($(window).width() / 2) - 400 + 'px'});
$('#modalClose').css({'display':'inline-block', 'top': ($
(window).height() / 2) - 320 + 'px', 'left':($(window).width() / 2) +
275 + 'px'});
if(mc == "get"){
$('#modal_inner').css({'left': 0});
$('#get_nav').addClass('selected');
} else {
$('#modal_inner').css({'left': '-476px'});
$('#share_nav').addClass('selected');
}
$('#greyBox').animate({'opacity':.8});
$('#modal').add('#modalClose').animate({'opacity':1}, function(){
if ($.browser.msie && $.browser.version == "6.0") {
$('html, body').animate({
scrollTop: $("#navPanel").offset().top
}, 1000);
}
});
}

BH.Modal.goto = function(mc){
if(mc == 'get') {
$('#modal_inner').animate({'left': '0px'}, 1000, function(){
$('#get_nav').addClass('selected');
$('#share_nav').removeClass('selected');
});
} else {
$('#modal_inner').animate({'left':'-476px'}, 1000, function(){
$('#get_nav').removeClass('selected');
$('#share_nav').addClass('selected');
});
}
}

BH.Modal.closeMe = function(){
$('#modal').add('#modalClose').animate({'opacity':0});
$('#greyBox').animate({'opacity':0}, function(){
$('#greyBox').add('#modal').add('#modalClose').css
({'display':'none'});
});
}