The credit card Year field allows only one number to be entered. I finally got it to go through by entering 2 in Year and 1 plus the card code in the Code field.
Other than that, it was fun and easy to use the site. I'm so excited to see the earrings in person. Thanks!
Update: The earrings arrived today and are even better than expected! Excellent quality! I know I will enjoy wearing them often.