I have no way of knowing since it's not on our end, but just a wild guess, it might have something to do with the country. Perhaps if you deleted the Japan items?
I know this isn't convenient, but you could
1. Delete half the items
2. Test it
3. If it doesn't work, go to Step 1.
If you still have 1 item in the List and it doesn't import, that would be very odd.
bidslammer