Conquest of the Horde

Hello CotH. I'm attempting to create myself a new account but have run into somewhat of a snag. On step 3 of the process, the actual Account Creation, I get an error telling me my account name doesn't match my forum name. Spelling is correct, e-mail is correct, so I'm a bit curious as to why it's not working. Anyone have some advice?

Keep in mind it's case-sensitive, so any capitalization in your account name or email must be matched.