If it is telling you that your e-mail address is in use, it is likely that you already have an account here (either from longer ago, or an application was approved that you had forgotten was sent in, or something). In either case, you can use the Lost Password feature to have the information for the account tied to that e-mail address mailed directly to you. Be sure to turn off any spam blockers or filters that might interfere with your receiving the mail.