MYSQL error

[dlewisr]

Database error in vBulletin :

I am getting the error below on my forum, there were no problems last night but
when I got up this morning this is the message I got. Members are taken to 500
internal server error when they click the what's new and also on the
unreadposts or New Posts.


Database error in vBulletin :

mysql_connect() [<a
href='function.mysql-connect'>function.mysql-connect</a>]: Can't
connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
/home/xxxxxx/public_html/includes/class_core.php on line 314

MySQL Error :
Error Number :
Request Date : Monday, June 20th 2011 @ 05:14:11 AM
Error Date : Monday, June 20th 2011 @ 05:14:11 AM
Script : http://www.xxxxxxxx.co.uk/misc.php?show=ccbmessages
Referrer :
http://www.xxxxxxx.co.uk/showthread.php/419-xxxxxxxxxx
IP Address : 194.66.200.1
Username :
Classname : vB_Database
MySQL Version :


Any ideas or suggestions anyone? I've contacted the server who said it maybe because they have updated to php version 5.3.6 which is my version anyway, so sounds lame. I've asked them to locate and analyse the error logs as there is no error showing in the logs when I looked.

Open to suggestions?
Cheers in advance