Bunu düzeltmek için nasıl anlamaya olamaz:

Warning: file_exists() [function.file-exists]: open_basedir restriction in effect. 
File(./codeigniter/logs/log-2010-11-12.php) is not within the allowed path(s): 
(/var/www/vhosts/example.com/httpdocs:/tmp) in 
/var/www/vhosts/example.com/httpdocs/codeigniter/libraries/Log.php on line 92