You may get an "Internal Server Error" to check in your apache error log,

#  tail -f /usr/local/apache/logs/error.log



[Sat Aug 30 12:15:56.716084 2014] [core:error] [pid 325205:tid 140117853251328] [client 1.22.171.226:59752] End of script output before headers: index.php

If you may get an above error,

To change your PHP latest version.