Yup...had that. It just would not let me send because it said: Cannot send a message; you have no characters to send as!
Good news though it is now working thanks to you! I entered all three keys. I only had one entered and it was not the right one.
As a side note, I fully recommend this function to anyone playing Layo. It is a superb IC way of getting messages to people in game and it will make you feel all warm and fuzzy inside when a bird drops a note at your feet...