Hey, I've got an issue with the checkout process. After a user has submitted billing & shipping information, and selected shipping & payment methods etc. If they then click off the checkout process, when they return the website breaks completely and they're just displayed this message in a red box:

EntityMetadataWrapperException: Unable to get the data property type as the parent data structure is not set. in EntityStructureWrapper->getPropertyValue() (line 442 of /profiles/commerce_kickstart/modules/entity/includes/entity.wrapper.inc).

Other threads suggested running Commerce Repair, which I have done, but with no luck.