VM not working if I switch Joomla in Italian

Hello everybody,
I bought Installation service for E-Commerce template.
Every thing works fine until I switch Joomla in Italian from Language Manager: in this case VM goes in error and doesn't recognize products and categories.
Mr. Milo, the operator who installed the template, told me to ask here support. I hope that somebody will be able to help me.
Thanks in advance.

See this:

www.hotjoomlatemplates.com/support-forum...uemart-problem#16942

and this:

www.hotjoomlatemplates.com/support-forum...d-languagepack#14140