I had the same issue and upon inquiring with Apple, received a reply as follows:
+"Having reviewed your account, I found a glitch in the communication portion of our server, specific to the server which your account resides on. As this is beyond my capacity to resolve at my current level, I have informed our engineers of this issue so that they can resolve this issue for you. As soon as I hear back from them, I will let you know that the issue has been resolved. Until then, have a great day, and thank you for being the best part of iTunes! :)+
Since then I tried again, but the problem remains unresolved. At least, I assume, someone is working on this.