/public_html/register/system/config.php file needs to be set to read and execute modes (644 or 755) to keep it secured from editing!
/public_html/register/index.php file is writable. It is recommended to set read and execute modes (644 or 755) for this file to keep it secured and running properly!
I have checked the files and have set them both to 755. I delete the messages from the message manager. When I login again, the messages are back again.