Problem with mail.module

I am running Drupal 4.4.0 and have installed the mail.module. This is a LAMP set-up. If you include any of the variables (%username) I get an error.

Warning: sprintf(): Too few arguments in /home/domain/public_html/includes/database.mysql.inc on line 44

Fatal error: Query was empty query: in /home/domain/public_html/includes/database.mysql.inc on line 97

Also is there a reason for having two message and roles selection boxes on the form. If you enter the text in the top message form it clears on preview. If you enter it in the bottom message box, it duplicates it in the top message box on preview.