If your domain is blocked when trying to complete a payment, you need to register your domain in the Bambora administration. Go to Settings -> Payment system to set up your domain.
If you've already set up your domain, please see the entry What does “Referring domain is not allowed/URL not allowed for relaying” mean?
You have access to one domain by default, but you can buy more. Please contact us if you need more domains.
Currency codes are available in the Bambora administration in the menu Support -> Currency codes and on our website here.