Grey Mare and others . Thanks to Semiannualchick's help,I have now learned why I couldn't send dialogs or recieve dialogs.
In order to be able to receive a PM (dialog) , you must go to the "manage" tab, and uncheck the box where it says "prevent new dialogs being sent to you".
I did not click that so I am assuming that it is a default setting.
Just FYI.