From Bugzilla Helper:
User-Agent: Opera/8.0 (Windows NT 5.0; U; en)

Description of problem:
simple example:
<?
  mail('username', 'Subject', 'Body');
?>

produces:

Fatal error: Call to undefined function: mail() in ....

Version-Release number of selected component (if applicable):
4.3.11-1.fc2.1.legacy

How reproducible:
Always

Steps to Reproduce:
1. create mail-test.php from the example above
2. open it with browser http://localhost/mail-test.php
3. 
  

Actual Results:  Fatal error: Call to undefined function: mail() in /home/.../mail-test.php on 
line 2

Expected Results:  Message must be sent to username

Additional info:

It seems like php was compiled without MTA support: http://fudforum.org/forum/
index.php?t=msg&goto=22109&

I use Plesk 7.5.3 on this server. It replaced sendmail with qmail.