Millielou:
Sorry the above should have said there is a problem connecting to our database NOT site is down for maintenance!
That error refers to your CONFIGURE.PHP (found in /includes/ and /admin/includes/ directory) and the provided DATABASE details being incorrect.
CHECK THIS SECTION:
// define our database connection
define('DB_TYPE', 'mysql');
define('DB_PREFIX', 'zen_');
define('DB_SERVER', 'YOUR DATABASE SERVER e.g. LOCALHOST');
define('DB_SERVER_USERNAME', 'USERNAME');
define('DB_SERVER_PASSWORD', 'PASSWORD');
define('DB_DATABASE', 'DATABASE_NAME');
define('USE_PCONNECT', 'false');
define('STORE_SESSIONS', 'db');
// for STORE_SESSIONS, use 'db' for best support, or '' for file-based storage
I hope that helps