Having quite the trouble registering for an account

[angelXboy]

I'm at the part where you input your DOB, user, pass and all that

apparently my username doesn't work because

http://i.imgur.com/bI3ut.png

What is that suppose to mean? Am i doing it wrong?
Is there a certain way i must type my user?
I tried Hiragana, full width katakana on IE BUT NOOOO THAT AIN'T WORKIN' SISTA.

[Sizustar]

Use English

[VonHalford]

use the guides we made in the sticky forum too. And use english