SQL ERROR [ mysqli ] Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (111) [2002]

These are common error messages to see when the database for a site has gone kaput. In short: no database, no website. In long: same thing.
The ton of crap you see below it on the page (called the "stack trace") looks complex, but is ultimately pointless. The purpose is for a coder to find the broken part of code and fix it, but the code isn't broken.
The database has been on the fritz for months now, with various parts of the site failing as it reached its limits (no more signups, no more PMs, and now the entire database has buckled).
The database will never be recovered without the admins.
There's not much more to say about it.
Source: I'm a programmer and web developer with experience in mysql, php, phpBB, and server administration.