innobackupex-1.5.1 --apply-log fail - error 2002

xtrabackup restore failed
i have an xtrabackup restore keep failing. this is what i get from xtrabackup:

[root@server xxxxx]# innobackupex-1.5.1 --apply-log /home/xxxxxx/backupInnoDB Backup Utility v1.5.1-xtrabackup; Copyright 2003, 2009 Innobase Oy.All Rights Reserved.This software is published under the GNU GENERAL PUBLIC LICENSE Version 2, June 1991.IMPORTANT: Please check that the apply-log run completes successfully.At the end of a successful apply-log run innobackupex-1.5.1 prints “completed OK!”.110423 13:07:25 innobackupex-1.5.1: Starting mysql with options: --unbuffered --110423 13:07:25 innobackupex-1.5.1: Connected to database with mysql child process (pid=16040)innobackupex-1.5.1: Error: mysql child process has died: ERROR 2002 (HY000): Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’ (2)[root@server xxxxx]#

does anyone know why this is failing?

I have no idea. Can you connect to the server through that socket file from the command line?