Temporary Passwords Not Being Emailed

I noticed A problem with our WordPress account today. We have WordPress 2.9.2 installed on our server. When someone clicks register on our website, they are directed to register for a WordPress account. The temporary password is never emailed to the registrant though. I have tried with several types of email accounts and checked in spam folders.

Where should I be looking to resolve this issue? It really creates a problem if people cannot register for our website. Any help is appreciated.

Thank You!