This are the osTicket system logs, they are not the logs for PHP or Apache.
You would have to consult your HTTP config to see where the webserver logs are located to see what is going on there.
You would have to consult your PHP.ini to find out where your PHP error logs are located to see what is going on there. If you cannot find your PHP.ini please create a text file in your web tree with the contents of <?php phpinfo(); ?> and browse to it. It will tell you the location of your php.ini and your error log. Remember to delete this file after, as it reveals a lot about the configuration of your server.