I had the EXACT same thing happen to me at the same hotel (W|Suites) .. the reservation disappeared - I booked again and they contact me that I had two reservations. Good thing u printed it out .. I didnt.

Watch it with your stay credit/starpoints at that location (Im there almost weekly) -- I usually have to have them added after the stay or sent to Lurker for help (only the web-rates .. some of the other rates do go thru).