Warning and Fatal Error with multiple coupon

I have some problem with multiple coupon
If I insert two coupon in the same moment, with semicolon separator, the site return to me that the coupon is invalid.
if I insert two coupon in two separate steps, the first one it's ok, applied the discount.
when i Insert the second one, the url go to "index.php?option=com_virtuemart&view=cart&task=edit_coupon&lang=it" and the page is a classic page without css style and two error string

1- Warning: Invalid argument supplied for foreach() in /home/####....###/templates/..../html/com_virtuemart/cart/default_pricelist.php on line 36

2-Fatal error: Call to a member function createPriceDiv() on a non-object in /home/###...##/templates/....../html/com_virtuemart/cart/default_pricelist.php on line 147

I have rupostel opc, and this error comes out both with opc enabled or opc disabled.
I tested also the virtuemart default template, and it display the same errors


my configuration is:
Joomla 2.5.7
Virtuemart 2.0.10
AwoCoupon 2.1.1

sorry for my bad english

Hello,

I could not reproduce the problem. Can you send me a private message with instructions to reproduce it on your site?

The errors received are received because of the page you are forwarded to, I receive those to if i go there manually.