I booked a EWR-AMS flight for later today on Delta.com. It's a Northwest flight operated by Delta. When I went to check in yesterday on Delta.com, it would not let me check in and said I should check in at the gate. It said "NSA", no seat assignment.

On the booking class, it said U for my first leg (AMS-JFK), and V for the EWR-AMS leg.

The Delta fare chart at http://www.cwsi.net/delta.htm shows V class as First/Business Elite via segment on domestic, and NA for international.

How can I have booked a V booking class fare on an international flight and what does it mean?

Thanks.