title: PHP calls to external programs all fail with exit code 127
body: <pre><code>echo system("/usr/bin/whoami", $ret);
  echo $ret;
  </code></pre>
  
  <p>PHP 4.3.9 on Apache 2.0.52, CentOS 4.5. Safe mode is off, I can run programs as the apache user account from the command line, but all programs run from PHP fail with exit code 127.</p>