Booking refugios in the Picos de Europa

This is probably because they are using the MasterCard SecureCode and Verified by Visa security system (I see the logos there). If your credit card doesn't have that set up (and many don't), then the blank screen can be when they send out for that special approval and don't get any data back. This is an issue with many European web sites, but I've had better luck with my Capital One card than my Bank of America Card. Also be sure to let your bank know that you're traveling.

Laura,
Thank you so very much for your reply - I just checked with Visa and I am covered by the Verified by Visa program, actually tried the transaction while they were on the phone. No luck. Same message.
Any ideas how I might determine if the reservarefugio website itself is working properly? Or how to contact the "Guard Association of Shelters" - the group behind the transaction??

Does the site give you a PayPal option? We had similar problems with bus tickets last year, even after calling our bank.

Dear Wonderful from Spain,

Thank you so much for trying the site - and no, we never got a message that the refugio was full, all of the July dates were entered apparently were available, it was at the payment site were we got an error message immediately upon hitting submit. And, all of the emails I have sent to the refugios bounced back "undeliverable" ????
But - I just got an email from a fellow at Collado Jermoso who happened to be vacationing in Utah, where I live, so at least I have one personal connection.
I will try calling these refugios, hopefully the phone numbers are better than the email addresses!

Travel Gal