805a01f4 error when attempting to make a payment on the marketplace. Is anyone familiar with this?

To be more precise, this happens when I try to remove ads from within 6tag. The store works, but this error has been persisting since last night, on each attempt. A little digging around reveals the error is not that uncommon, but there's no official response to it, yet.

The store works fine, I've just installed an app to test it.

Screenshot: http://i.imgur.com/QEh7AvL.png