Got the same error.
I tried to do the same things with a different account and it worked.
I switch back and same error pops.
Also tried in some other computer. Same error.
Sent an email to apple.
Got an reply to get screenshots to them. Sent.
Heres the last reply:
"Dear Costumer X,
Thanks for the reply. I have reviewed your screenshots, and it looks like this is a network issue. Everything on your account seems normal.
For this issue, you may need to call our AppleCare technical support team. A technical Advisor will be able to tell you about Apple's complimentary and fee-based support. The technical Advisor can also assist you in determining what option might be most helpful to you in this case. To find the appropriate phone number, please visit:
http://www.apple.com/support/contact/phone_contacts.html
Another option is to describe your issue on our website. After you have described the issue on our website, you can arrange for an Apple Advisor to call you. You can receive a phone call now or you can make an appointment to have an Apple Advisor call you at a more convenient time. To explore this option, please visit Express Lane:
https://expresslane.apple.com/
Certain Express Lane Support options are only free during your Apple hardware product's complimentary support period or with an AppleCare Protection Plan.
Thank you very much for being part of the iTunes Store family, Ricardo. I hope you have a great rest of your day.
Sincerely,
employee X"
I feel that this answer was a different way to say:
"We have no idea whats happening or how to fix it. Maybe hearing our voice will make you feel better. Good luck!"