There's more to the error but I figure that's the meat of it. Let me know if you need the rest of the error.Field 'topic_last_poster_name' doesn't have a default value
Here's how I migrated the database:
1) DB backup and download from old site's admin pages.
2) In phpmyadmin on my new site, I created a db and then imported the gzip file I downloaded.
3) Deployed phpBB on my new site.
4) Changed the values in config.php to point to the imported db.
For the record, I searched for a solution but the only page I found was on the currently hacked phpBB boards, which I can't get to.