mySQL error

[Boofo]

Can anyone tell me what the following error means:

Database error in vBulletin :

Link-ID == false, connect failed
mysql error: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

mysql error number: 2002

Date: Thursday 02nd of May 2002 05:04:28 PM
Script: /vbulletin/index.php
Referer:

I got this sent to me by my message board when (I think) no one was on, or if they were, no one has written me yet.

[FWC]

It most likely means there was a problem with mySQL. You get that when it crashes or goes away.

[Boofo]

So, it's really nothing to worry about then? Could it still give that error even if no one was on the message board at the time? If so, how, if the mySQL wasn't even be accessed at the time? I'm really curious now. :-) (Can you tell how new I am to all of this mySQL stuff? :-) )