WP login not working.

Members can’t reset there lost passwords. They’re told to go to there email and click on the reset password link that was sent. Which then tells you a new password has been sent.

The new password is never generated and received by the members. so now I’m stuck most of the day changing passwords. This happen when I upgraded to 3.0.

Is there a way to go back to my previous version of wp?

Thanks any info would be helpful.