My mail server complains that I do not have a Date: header in my mail, and it will not send it - Macintosh

No, this is not a bug. Eudora will not put a Date: header on you mail if you haven't set the correct time zone information on your Macintosh. You can set the time zone using the Map control panel, or, if you have System 7 Pro or System 7.5, the Date and Time control panel. Remember to change your time zone for Daylight Savings Time so that Eudora can set the Date: header correctly.