Virtuemart cart and child products do not work with mootools and javascript

Hi, i have a joomla/virtuemart site (2.5). Suddenly the cart and custom fields (child products) stopped working. I use child products for different sizes. When u choose a size the price is updating. Now its not. The add to cart is not working as well. If i disable mootools the add to cart works without pop up but i need the pop up. I suppose its a jquery error and some conflict with the gavick template i use and virtuemart. I have tried jquery easy to load only one instance of jquery but nothing happened.