From what I know about WordPress, that means that there's an error in establishing a database connection - which either means that the username and password information in the wp-config.php file
is incorrect (not at all likely!), or that WordPress simply can't contact the database server at localhost (very likely).
Translation: John Chow's server is either temporarily down or temporarily overloaded. John, are you still alive, my friend?
Update: John Chow is back online now. Hey, that rhymes. Sing it with me folks! John Chow...is back online now. John Chow...is back online now. La la la.
As it turns out, the whole mishap was apparently due to the WordPress plugin called Comment Relish, which crashed the MySQL database and totally maxed out the server load.