It sounds like you got this message:
"Error Code: 005-6499: The Club Nintendo servers are currently undergoing maintenance, so your user name could not be registered. Please try again later. "
The Wii shop, DSI shop, and the Eshop were all undergoing server maintenance recently, but this Club Nintendo maintenance is probably for a different reason. Even though nothing about it has been said yet, I would assume this maintenance has something to do with the Ambassador.