From www.wdwinfo.com

Disney plans maintenance for their reservation systems
Jun 11, 2013

Disney's reservation system will go down for maintenance Wednesday, June 12, at 3:00am EST until late morning Wednesday, June 12. This is for Walt Disney World, Disneyland, and Aulani. If you need to make a payment, you should do so before these dates to ensure you will not be late. You will also not be able to make reservations for dining, dinner shows, tours, recreation and children's activity centers as well as Cirque du Soleil at Downtown Disney. You will also be unable to access Disney's online check-in service.