In many Continental European countries the postal/zip code comes before the city, so I guess it's an understandable mistake, or, if they used a computerized system, it might have been unavoidable.
That's why with my recent online Zweitausendeins orders, I put my city and state in the first, smaller space designated for postal code, and put my zip code in the second, larger space designated for "place" (and did a similar reversal on the address line). Seems to have worked.