Help with a WordPress website host change

I have recently moved a website for a church. Their domain name did not change, only the webhost. It is now on a server I lease as a non-managed Linux box. I have about ten WP sites on it running with no problems.

I have moved WP sites before, but never had this problem. I have imported the sql database, changed the config file to represent that change.

I changed DNS, including the A record,

The front page loads okay, including a slider, (the slider however loads very slowly) the links show up on the bottom left hand corner with the correct sgacchurch.com/page, but the page errors.

If I try to access the wp-admin page I get an error stating that the ‘insert old database name’ is down, or the config page is wrong.

Any help would be greatly appreciated.
The website is http://www.sgacchurch.com/
admin is http://www.sgacchurch.com/wp-admin

Please help!!!
Tab Smith