This means that you signed up for your Yuku account with a "local" username on the Parris Island board, rather than a "global" username
that can be used on any board. Here is what Yuku suggests:
If the username is available globally, the user can put in a help ticket and ask the staff to change it. As long as it isn't taken on Ezboard or Yuku, they can change it for them.
As far as the quirk of creating all usernames local names, that's something that is being looked into as it's been a bit of an issue. We've been told they are attempting to either reword the instructions or do something a bit more drastic to keep people from making local accounts when global are available. The way it's set up it's supposed to automatically default global, but there's something currently preventing that.
Axel