I got an email entitled "Celebrate Your Anniversary with a Free Night On Us" on 31 July. It just told me to watch my mailbox.

My card anniversary was apparently 15 September, on which date I received an email entitled "Your Free Night eCertificate has arrived" -- certificate expires 13 September 2012, so it's good for 364 days, not a full year :-)

But the point is that the email with the "certificate" comes a monh and a half later.

Email arrives from Priority Club Rewards <[email protected]> so you might want to add that email to your "Safe Senders" list or equivalent to reduce the odds it ends up in your SPAM folder.

Moreover, there is actually no certificate -- the email merely tells you to:
I'm disappointed I can't book the free night online.
I would check availability at your hotel; I presume if Reward Nights are available you should be able to book a night on the phone.

But the point is if you're waiting for your certificate, don't worry, just call the above number and they should be able to look you up and book you.