ok, riporto da riga 25 a riga 32 del file.

// Try to bypass include path for best performance
$filePath = str_replace('.', '/', $class) . '.inc.php';
if (file_exists(BASE_SYS_DIR.'/'.$filePath)) {
include_once BASE_SYS_DIR.'/'.$filePath;
} else {
// Oops, we found a legacy include statement,
// let's try the include path then.
require_once($filePath);