When you get the error, view the page source for that page and you will see the actual database error near the bottom of that page. It will have some information like this:
Code:
The actual mysql query/code/problem....
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
We need to see that in order to help. So ask your mod to get this information.
I'm actually surprised that you, the owner, are not seeing these errors. Do you have your email entered into the config.php file to get all database errors?