opening screens or maps in the monitoring section produces the following error :
Use of undefined constant S_add_TO - assumed 'S_add_TO'[/srv/www/htdocs/zabbix-1.7/maps.php:171]
and [/srv/www/htdocs/zabbix-1.7/screens.php:260]

locale files use an all-caps version (S_ADD_TO), so it is assumed these strings also should be all uppercase.