Description:
------------
Running Joomla with lighttpd, fastcgi, mysql.
About 1 in 5 loads of alternating pages, an error is encountered where
is_readable($path) is true, but the include fails. The file system has
plenty of space, the file does exist, permissions are correct, and 
the file is loaded successfully the other 4 times.

The code snippet below will sometimes fail with "Include failed"
and then a subsequent reload of the page will succeed with "Include Success"
-----------------------------
$path = 'somefile.php';

if (is_readable($path)) 
{
    $retval = include $path;
    echo '<span class="note">Include retval='.$retval.'</span>';
    if ($retval == '')
    {
      echo '<span class="note">Include failed</span>';

    }else
    {
      echo '<span class="note">Include Success</span>';
    }
} else 
{
        echo '<span class="note">File not readable</span>';
}

Test script:
---------------
$path = 'somefile.php';

if (is_readable($path)) 
{
    $retval = include $path;
    echo '<span class="note">Include retval='.$retval.'</span>';
    if ($retval == '')
    {
      echo '<span class="note">Include failed</span>';

    }else
    {
      echo '<span class="note">Include Success</span>';
    }
} else 
{
        echo '<span class="note">File not readable</span>';
}

Expected result:
----------------
Include Success

Actual result:
--------------
Include failed