SkyFire: The item you’ve requested is not currently…

Hello friends,
I tried to load music from iTune store for several times, but every time it says "the item you're requested is not currently available in the US store.". I used iTune several time before, but such kind of message did not appear anytime.
I don't know why it happens but need to know how to overcome the problem.

Error message:
Your request could not be completed.
The item you’ve requested is not currently available in the US store.
Best wishes,
Evana
