Database error in vBulletin :

mysql_connect() [function.mysql-connect]: Access denied for user 'root'@'localhost' (using password: NO)
/home/***/public_html/vb1/includes/class_core.php on line 309

MySQL Error :
Error Number :
Request Date : Monday, November 21st 2011 @ 05:26:19 PM
Error Date : Monday, November 21st 2011 @ 05:26:19 PM
Script : http://www.***.com/vb1/install/upgrade.php
Referrer :
IP Address : *************



Username :
Classname : vB_Database
MySQL Version :