Installing and upgrading help

Our school recently set up its own moodle site (version 1.8.4) by installing PHP 5.1.2, MySQL 5.0.18 and Moodle with Mac OS 10.4.11 on a standard client Intel Mac (not server version) to be used as a production server. The new installation works for new users. They are able to create new accounts, receive email notifications, and enroll in courses. We also migrated four existing courses from a district server ( version 1.5.4 ). The courses and users all appear on the new server but users are unable to login. When the ‘Forgotten your user name or password option’ is enacted, email notifications are successfully sent out to the user with new passwords but the new passwords don’t work either.