In auth.php, auth_sendPassword, the user's name is concatenated with their email address and sent into mail_send as the "To" parameter. This produces a "username <email@example.com
>" string which the Windows version of php rejects.
"Note: The Windows implementation of mail() differs in many ways from the Unix implementation. ..blah blah blah
As such, the to parameter should not be an address in the form of "Something <firstname.lastname@example.org
>". The mail command may not parse this properly while talking with the MTA. "
The quick fix to this is to send only the email address as the To param in mail_send from the auth_sendPassword function.