I can confirm that the booking system of the albergue in Roncesvalles works fine. I was able to start a booking for 22 April 2018, went through the various steps and got to the page where you enter your credit card details to pay. Try this link, it's already set up for English:
http://www.alberguederoncesvalles.com/index.php?idioma=2
Make sure that your browser does not do automatic translations from Spanish to English as this has caused errors in the past and made bookings impossible.
The Roncesvalles albergue is not on Booking.com - you need to use their own booking system which is new and was set up last year I think.