When you try to translate the registration page with Google, it tries to use Chinese (simplified Han), but it doesn't translate because the page is Chinese (traditional Han). Just force Google to use traditional Han, and it will translate perfectly.
Also, as the second post stated, the QQ number is optional.
I am having trouble signing in the "Online Backup" app on MIUI. It say to go to MIUI.com if you are having trouble so I went there then clicked on the Orange MIUI box in the top left corner and registered at the pop up on that next page. I am signed in ok with this website but when I return to the Online Backup app on my phone I still cant sign in properly.