I just installed a version of 2.0.26 VM invoice.
Using Joomla 2.5.11 and Virtuemart 2.0.20b
Every time I try to go in managing orders / invoices (Invoice / Order Management) I get the following error:

500 - Si è verificato un errore.

DateTime::__construct() [datetime.--construct]: Failed to parse time string (-001-11-30T00:00:00+00:00) at position 7 (-): Double timezone specification

What should I do?
I bought the component specifically for the management of the change order.

Giovanni Stolzi

No answer?
Where is the ARTIO support?

I have the same problem. It is urgent to solve.