Critical Error occured

Errordetails:
Database error: Link-ID == false, connect to localhost failed
mysql error: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (111)
mysql error number: 2002
Date: 30.01.2012 @ 03:33
Script: /src/index.php?&serverid=1
Referer:

Warning: Unknown: open(/var/lib/php/sess_106748574631b4e95102e7f40fd51d4b, O_RDWR) failed: Read-only file system (30) in Unknown on line 0

Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/var/lib/php) in Unknown on line 0