UBB.threads PHP Forum Software Community Forums UBB.threads Version 7/8 Support Temporary Password email not being received

Can anyone tell me how/ where I can repair the 'Enter the email address or your Username to have a temporary password mailed to you.' link fixed so that a temporary password is actually sent to people?

This is the page http://www.thechartist.com.au/forum/ubbthreads.php?ubb=login&lostpw=1

We are using version 7.5.2

Many thanks
Trish