error code undefined method stdClass::setCartIntoSession()

I am using Joomla 2.5 and VM2, when I customers try to input a coupon in the cart they get this error:

Fatal error: Call to undefined method stdClass::setCartIntoSession()

What does that even mean?!

Hello,

This is a function within Virtuemart to set the shopping cart, called from AwoCoupon. Are you using some type of one page solution? I have seen the cart not being set when using a one page. I believe this error was fixed in Awocoupon 2.0.6. What version are you using?