MooTools event not triggering in IE9 (only after refresh) - mootools

Question

I changed the entire question because I didn't provide enough info's at the first run: thanks goes to #Sergio.
There are alot of things not working in IE.
When I do addEvent('domReady').... It's even more bad(it doesn't gets executed but if I refresh the page... it works).
Is there a proper way to handle that IE stuff in MooTools?
note:
working on every browser on the whole planet except IE*
edit: added the complete source code of ajax cart.
This code it correct, it's just for understanding purpose only:
ajax_cart.js
var AjaxCart = new Class({
Implements: Options,
cartDiv: null,
options: {
elem_id: 'shopping-cart-icon',
event: 'mouseenter',
url: 'changed_url_but_it's_correct='+(new Date().getTime())
},
var AjaxCart = new Class({
Implements: Options,
cartDiv: null,
options: {
elem_id: 'shopping-cart-icon',
event: 'mouseenter',
url: '/changed_url_but_it's_correct='+(new Date().getTime())
},
var AjaxCart = new Class({
Implements: Options,
cartDiv: null,
options: {
elem_id: 'shopping-cart-icon',
event: 'mouseenter',
url: '/changed_url_but_it's_correct'+(new Date().getTime())
},
initialize: function() {
var cart = this;
this.elem = $(this.options.elem_id);
if (this.elem) {
this.elem.addEvent(this.options.event, function() {
cart.viewCart();
});
}
},
getCart: function() {
var cart = this;
var myHTMLRequest = new Request.HTML({
url: cart.options.url,
onSuccess: function(responseTree, responseElements, responseHTML, responseJavaScript) {
//console.log(responseHTML);
if (!cart.cartDiv) {
cart.cartDiv = new Element('div', {'class':'ajax-cart'});
cart.cartDiv.fade('hide');
cart.cartDiv.inject(cart.elem);
cart.cartDiv.addEvent('mouseleave',function() {
this.fade('out');
});
}
cart.cartDiv.innerHTML= responseHTML;
cart.cartDiv.fade('in');
},
onFailure: function(xhr) {
console.log(xhr.responseText);
}
}).get();
},
viewCart: function() {
if (this.cartDiv) {
this.cartDiv.fade('in');
} else {
this.getCart();
}
}
});
This code works on every browser except IE, only after refreshing the page, it works.
in index.html
if(Browser.ie) {
var ajaxCart;
window.addEvent('load', function() {
ajaxCart = new AjaxCart({'elem_id':'shopping-cart-icon'});
});
} else {
var ajaxCart;
window.addEvent('load', function() {
ajaxCart = new AjaxCart({'elem_id':'shopping-cart-icon'});
});
}

Answer 1

In some versions of Internet Explorer (ie. IE6) a script tag might be executed twice if the content-type meta-tag declaration is put after a script tag.
The content-type should always be declared before any script tags.
See here http://mootools.net/docs/core/Utilities/DOMReady

Answer 2

I guess there is no solution so I had to find a workaround for this.
What I did:
Since my problems were solved by refreshing the page, I did this in meta tag.
<meta http-equiv="Expires" content="-1" />
It might help someone else, when it comes up to fixing IE refreshing bugs.