Cannot purchase in ubuntu software centre: incorrect xml error

[Woody]

I cannot purchase the game "Amnesia: The Dark Descent".
Everytime I try to make the payment it says:
Your payment was unsuccessful
Your payment could not be processed. Please verify the submitted information.

Reason: Incorrect encoded XML

Why?
I can't buy the game! and the 75% off discount ends 3rd november :(
Here on the forums a couple of others have the same problem: http://ubuntuforums.org/showthread.php?t=2077115

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1074580/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.