The problem is, our system no longer allows user names with "special characters," including puncuation marks like the period in yours. It still allows legacy accounts to work, but even mods and admins can't update them.
The only solution is to change your user name to one that doesn't include puntuation. The user name, aka was already registered, but that member registered in 2000 and made only four posts. I renamed that account to allow you to have the name, AKA, if that is your preference.
You probably know we will soon (sooner is better!) be moving to vBullitin software. I don't know if it will be set to allow members to register names with punctuation. If it does, you can request a name change back to A.K.A. after the move.