Uncaught ReferenceError: Isotope is not defined

Hello,
after adding some products and deleting some of them i got an error "Uncaught ReferenceError: Isotope is not defined" and the product list of the specific page/category gets stuck in "Loading Products..." message. All other pages/categories are working fine. In order to fix i need to make a new page/category and reasign all the faulty products to the new page. OR i can make the faulty page work again if i apply a filter module to that page. That has happened to more than one website that i used isotope. I am using Mootools and Jquery.

Any ideas?

Thanks.

Just an update,
I can see the product list fine if i add a variable [isorc=1] with any type of value to the end of the url. That variable is used by iso filter module. That is working eventhought i haven't add any filter module to the page. For instance www.mydomain.com/index.php/category_name.html?isorc=1 works just fine. BUT if i go to www.mydomain.com/index.php/category_name.html i got stuck in "Loading Products..." message and an error "Isotope is not defined"