[BUG] Marketpress not charging for shipping on International orders

Having a problem with International orders in MarketPress -- seems the plugin is not charging shipping on international orders when the Provice/State/Region box is left blank.

WP Multisite 3.0.5
MarketPress 1.3.1

In the example in the attached images, we're selling a DVD for $12.99 with an international shipping price of $4 US.

When I go to check out and choose Switzerland for my country, there is no shipping charge if I leave the "state" box blank. On the other hand, if I put something in the "state" box, it will charge shipping.
http://thebutterflycircus.com/store/