Database error - can't connect to local MySQL server through socket

[leannet]

Does this error just happen or does it mean some one has been messing with the site?

<!--
Database error in vBulletin :

mysqli_real_connect() [&lt;a href='function.mysqli-real-connect'&gt;function.mysqli-real-connect&lt;/a&gt;]: (HY000/2002): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
/home/----------/public_html/includes/class_core.php on line 1138

MySQL Error :
Error Number :
Request Date : Monday, May 27th 2013 @ 06:37:23 PM
Error Date : Monday, May 27th 2013 @ 06:37:23 PM
Script : http://-------------.com/admincp/index.php
Referrer :
IP Address : 175.35.66.88
Username :
Classname : vB_Database_MySQLi
MySQL Version :
-->

--------------- Added [DATE]1369698881[/DATE] at [TIME]1369698881[/TIME] ---------------

I found this answer

If you are getting this error, it means either:

1. The info in your config.php file is wrong (in which case your forums wouldn't work at all), or

2. MySQL crashed, it's not running or it can't find the socket. You need to contact your host about this.

What if I can't contact my host ?