to find out which DB you are using, open includes/config.inc.php
you will see which DB that is being used..
after that, you can backup you DB in many ways..
ideally, if you are a small forum.. you could prolly use phpMyAdmin from your cPanel or equiv..
you also have the ability to use ubb.threads admin and backup tables individually (very slow)
additionally, (if you have it) you can shell into your box and back it up at the command line..
just depends upon the site / hosting package you have there
