Moved Host

I just moved to a new host and I get the following error on the admin login page

Warning: Cannot modify header information – headers already sent by (output started at /home/user/public_html/wp-config.php:47) in /home/user/public_html/wp-login.php on line 12

If I try to login as the login box is below that error I get a load more very similar error messages on a white page.