Errors After Upgrading

I just upgraded a site from WordPress 1.2 to the current version. I got it running and it’s connecting with the old database, but when ever I do anything in admin, post, manage, etc. I get this warning after I apply changes:

Warning: Cannot modify header information – headers already sent by (output started at /home/content/m/a/m/mamaofc/html/wordpress/wp-config.php:2) in /home/content/m/a/m/mamaofc/html/wordpress/wp-includes/pluggable-functions.php on line 272

The warning isn’t identical everytime (I think) but something like this. The changes do seem to take when I view the site. Can someone help me fix this? It will really freak out the other users.