error_log httpd

# tail /var/log/httpd/error_log
[Sun Sep 01 07:53:32.199598 2013] [:error] [pid 22627] [client ::1:36144] PHP Notice:  Undefined variable: lang in /var/www/html/public_html/index.php on line 5
[Sun Sep 01 07:53:32.199671 2013] [:error] [pid 22627] [client ::1:36144] PHP Warning:  include(lang/_lang.php): failed to open stream: No such file or directory in /var/www/html/public_html/index.php on line 5
[Sun Sep 01 07:53:32.199683 2013] [:error] [pid 22627] [client ::1:36144] PHP Warning:  include(): Failed opening 'lang/_lang.php' for inclusion (include_path='.:/usr/share/pear:/usr/share/php') in /var/www/html/public_html/index.php on line 5
[Sun Sep 01 07:53:32.199691 2013] [:error] [pid 22627] [client ::1:36144] PHP Notice:  Undefined variable: lang in /var/www/html/public_html/index.php on line 6
[Sun Sep 01 07:53:32.199711 2013] [:error] [pid 22627] [client ::1:36144] PHP Warning:  include(lang/_pages.php): failed to open stream: No such file or directory in /var/www/html/public_html/index.php on line 6
[Sun Sep 01 07:53:32.199717 2013] [:error] [pid 22627] [client ::1:36144] PHP Warning:  include(): Failed opening 'lang/_pages.php' for inclusion (include_path='.:/usr/share/pear:/usr/share/php') in /var/www/html/public_html/index.php on line 6
[Sun Sep 01 07:53:32.199724 2013] [:error] [pid 22627] [client ::1:36144] PHP Notice:  Undefined index: page in /var/www/html/public_html/index.php on line 8
[Sun Sep 01 07:53:32.199731 2013] [:error] [pid 22627] [client ::1:36144] PHP Notice:  Undefined index: page in /var/www/html/public_html/index.php on line 10
[Sun Sep 01 07:53:32.199751 2013] [:error] [pid 22627] [client ::1:36144] PHP Fatal error:  Call to undefined function query_db() in /var/www/html/public_html/inc/query.php on line 15