This error message is associated with the component K2. The component K2 bit incorrectly sets the route for their models in place, in which the route should not be placed. Ignore this message. It does not affect the operation IPrice minimart. This message will appear as long as you have installed the k2.
Technical details:
IPrice minimart do not use models for backend. But Joomla try to find model for each controller.
If including path for models is empty - no error message occured.
But the component K2 set include path for own models in general place. This path affects for all components. So, if the component has the controller with the same name as the controller of K2 (in this case it is controller "Item"), then Joomla try to find model for this controller in path, setted by K2. Joomla found model /administrator/components/k2/models/item.php , but can not find class named IpricecalcModelItem in this file. In this case Joomla send an error message for the user.
