Error on login page

I run a website for my church and have had it running for several months now. Everything was great, until I moved it from Yahoo’s servers to Blue Host. After the move, I’ve gotten the following error on the wp-login.php page.

Warning: Header may not contain more than a single header, new line detected. in /home4/southsj5/public_html/main/wp-login.php on line 304

After trying to login, I get the following message:

Warning: Header may not contain more than a single header, new line detected. in /home4/southsj5/public_html/main/wp-login.php on line 304

Warning: Cannot modify header information – headers already sent by (output started at /home4/southsj5/public_html/main/wp-login.php:304) in /home4/southsj5/public_html/main/wp-includes/pluggable.php on line 662

Warning: Cannot modify header information – headers already sent by (output started at /home4/southsj5/public_html/main/wp-login.php:304) in /home4/southsj5/public_html/main/wp-includes/pluggable.php on line 663

Warning: Cannot modify header information – headers already sent by (output started at /home4/southsj5/public_html/main/wp-login.php:304) in /home4/southsj5/public_html/main/wp-includes/pluggable.php on line 664

Warning: Cannot modify header information – headers already sent by (output started at /home4/southsj5/public_html/main/wp-login.php:304) in /home4/southsj5/public_html/main/wp-includes/pluggable.php on line 666

Warning: Cannot modify header information – headers already sent by (output started at /home4/southsj5/public_html/main/wp-login.php:304) in /home4/southsj5/public_html/main/wp-content/plugins/simple-forum/credentials/sf-credentials.php on line 113

Warning: Cannot modify header information – headers already sent by (output started at /home4/southsj5/public_html/main/wp-login.php:304) in /home4/southsj5/public_html/main/wp-includes/pluggable.php on line 865

I’ve gone through the wp-login file and the pluggable.php file, as well as the sf-credentials.php file. I couldn’t find any blank spaces at the start or end of the files, and it appeared to be correct everywhere else. Of course, I’m very much a novice so I may have missed something. I did notice that at each of the indicated lines in the error messages, it is using the setcookie command.

Lines 301-304 in wp-config.php:
301 //Set a cookie now to see if they are supported by the browser.
302 setcookie(TEST_COOKIE, ‘WP Cookie check’, 0, COOKIEPATH, COOKIE_DOMAIN);
303 if ( SITECOOKIEPATH != COOKIEPATH )
304 setcookie(TEST_COOKIE, ‘WP Cookie check’, 0, SITECOOKIEPATH, COOKIE_DOMAIN);

Lines 660-666 in pluggable.php:
660 // Set httponly if the php version is >= 5.2.0
661 if ( version_compare(phpversion(), ‘5.2.0’, ‘ge’) ) {
662 setcookie($auth_cookie_name, $auth_cookie, $expire, PLUGINS_COOKIE_PATH, COOKIE_DOMAIN, $secure, true);
663 setcookie($auth_cookie_name, $auth_cookie, $expire, ADMIN_COOKIE_PATH, COOKIE_DOMAIN, $secure, true);
664 setcookie(LOGGED_IN_COOKIE, $logged_in_cookie, $expire, COOKIEPATH, COOKIE_DOMAIN, false, true);
665 if ( COOKIEPATH != SITECOOKIEPATH )
666 setcookie(LOGGED_IN_COOKIE, $logged_in_cookie, $expire, SITECOOKIEPATH, COOKIE_DOMAIN, false, true);

Line 865 on pluggable.php:
header(“Location: $location”);

Line 113 in sf-credentials.php:
setcookie(‘sforum_’ . COOKIEHASH, stripslashes($dname), time() + 30000000, $cookiepath, false);

I added the line numbers at the start while typing this post, they are not part of the actual files. Any help anybody can give would be greatly appreciated. I also extracted a fresh copy of the wp-login.php from wordpress’ site and uploaded it in place of my file, no luck. I’ve since put my original wp-login.php file back in place. Thanks.