WordPress Website Migration Process

Hello,

I am in the process of moving some of my WordPress sites to a new server. I have done a lot of research on the web to figure out the least painful way to do this. The tricky part, I think, is that I do not want to change the domain names. I was semi-successful. Below are the steps I took:

1) Backed up the Database, WP Content, XML

2) I went into my new server and setup an Add-on Domain for an existing domain

3) I installed WordPress on the new server

4) In PHP My Admin, I imported my database sql file

5) I edited the WP-Config file to point to the new database, and uploaded it to the new and old server.

6) Pointed the DNS to the new server

7) Updated the permalinks

The site was down for a little while, but then it was live again, and I thought all was well. Now, when I visit the site it says that there is a database error. I can’t think of any good explanation for this. Can anyone shed some light on this matter? And maybe explain why I would see the sight working perfectly one day and the next day see a database error? Thank you very much! I appreciate any comments!