A couple of people have received the following message when attempting to post a message:
"Sorry, but we have no one registered with the UserName you typed. Please try again. Use your Back button."
Assuming you are properly registered, this usually is a case that you are not entering your user name *exactly* as you entered it when you registered.
User names are case sensitive, which means that if you entered it all lower case on registration, you must enter it all lower case when you are logging in. The same applies to any extra characters or spaces that you included in your user name.
For example, "tyl" is different from "Tyl" and "john_jones" is different from "john jones" the "underscore" character makes all the difference.