Email registration question

Okay, I took over for someone that had set up a clients website using WordPress. They did it on their own server and then moved it to another server. So when I took it over and installed cformsII I cannot get it working. Someone said it might be the email. I believe someone changed the email on the general settings page, but it wasn’t the email that the site was originally registered with. So I did a test. Tried to reset the password to his account, but when I put in the email that I believe it was registered with, it now gives me the error

The e-mail could not be sent.
Possible reason: your host may have disabled the mail() function…

So how do I change the email that it was registered with and solve both this problem and my cforms problem

Does this all make sense?