[ERROR] Server Error Log - PHP Notice:

[am-fs]

PHP Notice: Undefined index: sessdo in /var/www/vhosts/xxxxxxxxx.com/httpdocs/forum/arcade.php on line 24, referer: http://www.xxxxxxxxx.com/forum/arcade.php?do=playfull&gameid=30
[client 61.xx.xxx.xxx] PHP Notice: Undefined index: sessdo in /var/www/vhosts/xxxxxxxxx.com/httpdocs/forum/arcade.php on line 31, referer: http://www.xxxxxxxxx.com/forum/arcade.php?do=playfull&gameid=30
[client 61.xx.xxx.xxx] script '/var/www/vhosts/xxxxxxxxx.com/httpdocs/arcade.php' not found or unable to stat

How can i get rid of this

PHP Version 4.3.10
thanks

[am-fs]

Any ideas how to rid these errors, it fills my error logs daily.

Thanks