Hi Matt - If you get the time, could you look at this post http://our.umbraco.org/projects/collaboration/merchello/merchello/59930-Error-when-entering-shipping-in-merchello-settings and maybe steer me in the right direction.

I'm not sure this is an issue with Merchello (but it may be).

Also, I'd love to set up a Skype call sometime to chat about some of the things you've done in Vorto and discuss how it could be used when we start refactoring the Merchello products a bit ...

Much appreciated!