when I go to create a new username appears the following error

Fatal error: Call to undefined function mail() in /home/gnuworld/website/docs/gnuworld/cr_newuser.php on line 168

already I configured and I reconfigured php

Yes you have php , but did you checked if you have sendmail ?

tanks Dan I installed php5 and everything decided. Now plus no error not to put the email does not arrive for the customer
the post office with the password does not arrive at the user

try a: service sendmail stop/start/restart

Hi friends plus an error I believe that this finishes is it how much the users create its users receive an email with link

--->http://127.0.0.1/live/confirm.php?cookie=f189396196562064f383438597779fbd

when in the truth it would have to be

http://cservice.brasmirc.com.br/live/co ... 8597779fbd

what I must make to repair this error ?

Using the service sendmail stop/start/restart is a good way for that error. I think you should check the configuration of the post office for the mails for clients. There should be some conflicts on it.