To qualify for the SkyTeam Europe Pass you must have purchased an inter-continental ticket on Northwest Airlines or KLM Royal Dutch Airlines, in addition to one of the following from WorldVacations:

Hertz car rental for a minimum of three days
or
Two nights hotel offered through:
WorldVacations — a total of 99 hotels to choose from throughout Europe
Great Britain & Ireland HotelPass
France HotelPass
Best Western Advance