Problema de conexão DB

Database error in vBulletin 3.5.3:

mysql_connect(): Unknown MySQL Server Host 'MOS_HOST' (1)
/home/ez2cl/public_html/index/comunidad/includes/class_core.php on line 279

MySQL Error :
Error Number : 0
Date : Tuesday, February 14th 2006 @ 12:13:33 PM
Script : http://www.ez2dancer.cl/index/comunidad/admincp/user.php
Referrer : http://www.ez2dancer.cl/index/comunidad/admincp/user.php?do=edit&u=291
IP Address : 164.77.237.126
Username : Shanecito Matsura
Classname : vb_database

Clique para expandir...