Sorry guys to add to this, but I'm in the same situation than the OP and find the wording in the JAL confirmation email I got somewhat mysterious and am wondering if I need to do anything else.

I booked a flight from KIX to CTS in Class J for 2 pax on a Super SAKITOKU Advanced Purchase Fare and got the 4-digit reservation number. I also paid for the ticket already completing the purchase and according to my banks SMS my credit card has been authorized / charged.

The email I got had a passage stating the following:

Important notice about ticket purchase
Please purchase your ticket by August 25.
Purchasing Tickets/Payment
http://www.jal.co.jp/en/pay/
If you already have a ticket, please contact us by the above date to register your ticket number. Failure to do so may result in cancellation of your reservation.

If you have already purchased or registered your ticket, we thank you for your cooperation and please disregard this notice.

What is the part about registering the ticket numbere about? AnythingI have to do in that regard?

Thanks for any pointers