Do not use dropship if your sales document shipping method is a pickup method (which you can check in GP) and do not use any dropship shipping method directly on a purchase order.
Purchase orders cannot use a pick-up shipping method. Purchase orders will throw a country code (ccode) eConnect error if you try to use a pick-up method.
If you use a dropship method on a purchase order, it will try to pick up the shipping method on the underlying sales document. If that happens to be a pick-up method, you will get the country code error message.