UPDATE: Amnerys just posted on the EQ2 Forums:
We are experiencing some technical issues with the GameStop promotion in Europe. The European sale will be delayed by one day. You can go ahead and purchase the card already but don’t redeem them too early. Players in Europe should redeem the cards between Saturday, February 25th 12:01am Pacific Time and Monday, February 28th 11:59pm Pacific Time.
Buy SOE Pre-Paid Game Cards at participating GameStop locations now and redeem between Feb 24th and Feb 26th to get Double Station Cash! Redeem in-game or at www.soe.com/gamecards
Game cards must be purchased at Game Stop and must be redeemed between 12:01am Pacific Time 2/24/2012 and 11:59pm Pacific Time 2/26/2012 to qualify for double Station Cash.