When you get a page that says you have encountered a database error, you need to View Page Source for that page and at the bottom of the source is the full database error. Something like this:
MySQL Error : some sort of something here
Error Number : another something here
Date : Sunday, April 13th 2008 @ 11:16:43 AM
Script :
http://address.path.path/page.php
Referrer :
IP Address : **.***.**.***
Username : username
Classname : database