Issues reinstalling an old backup

[Daniel Thomas]

All right, I know there's already guide that explains how to reinstall the database but it's very vague in my opinion.

Here's my issue. I'm trying to reinstall a backup of an old forum that has been dead for 8 months. Using bigdump.php I reinstalled the database on our server and downloaded and then uploaded the core vBulletin files from the vB site, and modified the config file to access the new database, however I get a Database error screen when I go to the forum.

Was I also supposed to to backup the original files from the old server too, or is just the database sufficient? Is there something I'm supposed to run after I upload the database and files to make the forum read the database? Help would be greatly appreciated.