Fatal error: VirtueMartCart::prepareAjaxData()

[karckash]

Good Day,

i have joomla 2.5.9, and virtuemart 2.2.20b  and when i have a product long on cart then i try to move on another link on the web page appears the next error..

Fatal error: VirtueMartCart::prepareAjaxData() [<a href='virtuemartcart.prepareajaxdata'>virtuemartcart.prepareajaxdata</a>]: The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition &quot;VmImage&quot; of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide a __autoload() function to load the class definition in /home/thecaban/public_html/components/com_virtuemart/helpers/cart.php on line 1504