Error files being generated constantly at apache server

I am getting the following kind of error开发者_StackOverflows very fast and I am unable to open up my plesk control panel. My disk space is becoming full at very constant speed. Now I am unable to open up my ftp also. The disk space is rapidly being occupied with error log files.

These are the error messages I am getting. Can anyone please look into this..

[root@host353218 ~]# grep -Hr 94.233.235.239 /var/www/vhosts/playtoongames.com/statistics/logs/error_log | grep 09:12
/var/www/vhosts/playtoongames.com/statistics/logs/error_log:[Mon Jun 06 09:12:22 2011] [error] [client 94.233.235.239] PHP Notice:  Use of undefined constant LOGIN_TITLE - assumed 'LOGIN_TITLE' in /var/www/vhosts/playtoongames.com/httpdocs/lang/en.php on line 4, referer: http://www.playtoongames.com/categories/5/
/var/www/vhosts/playtoongames.com/statistics/logs/error_log:[Mon Jun 06 09:12:22 2011] [error] [client 94.233.235.239]

Regards.

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You are using a constant named LOGIN_TITLE in "httpdocs/lang/en.php", that is not defined before. It should be either a string (encapsed in quotes 'LOGIN_TITLE'), or you should define it before.

Update:

How to define a constant in PHP.

define('LOGIN_TITLE', 'Sign in');

The first argument is the name of the constant as a string, not as a constant itself. The quotes ' are required.