I found this article phpBB • Transferring Your Board to a New Host or Domain • 3.0 which was really helpful.
Everything appeared to have worked. All the messages were there and I was able to sign in. I went to post a message and got an error:
Field 'post_edit_reason' doesn't have a default value I googled the error and found this article: phpBB • Doesn't have a default value errors • 3.0
What happened was that the database had been upgraded from MySQL 4.03 to 5.2. The information in this article worked to fix the problem.