Network Mulisite Installation errors ???? help!

i’m pretty new at this and i would appreciate any and all help i can get.
after adding

define (‘WP_ALLOW_MULTISITE’, true);

to wp-config.php successfully create “network” option under tools, everything appears to work correctly.
(however if i attempt to log out at this point receive a page full of these errors:
Warning: Cannot modify header information – headers already sent by (output started at /home/design/public_html/wp-config.php:1) in /home/design/public_html/wp-login.php on line 337 )

other then that everything appears normal
i proceed to network install, sub directories
create blogs.dir in wp-content
add:

define( ‘MULTISITE’, true );
define( ‘SUBDOMAIN_INSTALL’, false );
$base = ‘/’;
define( ‘DOMAIN_CURRENT_SITE’, ‘designquoter.com’ );
define( ‘PATH_CURRENT_SITE’, ‘/’ );
define( ‘SITE_ID_CURRENT_SITE’, 1 );
define( ‘BLOG_ID_CURRENT_SITE’, 1 );

to wp-config.php above “thats all happy blogging”
then add

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ – [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

to .htaccess file..
click login again, brings me to the login page with these errors on top

Warning: Cannot modify header information – headers already sent by (output started at /home/design/public_html/wp-config.php:1) in /home/design/public_html/wp-login.php on line 337

Warning: Cannot modify header information – headers already sent by (output started at /home/design/public_html/wp-config.php:1) in /home/design/public_html/wp-login.php on line 349

i enter my username and password and it takes me to a full page of this:

Warning: Cannot modify header information – headers already sent by (output started at /home/design/public_html/wp-config.php:1) in /home/design/public_html/wp-login.php on line 337

Warning: Cannot modify header information – headers already sent by (output started at /home/design/public_html/wp-config.php:1) in /home/design/public_html/wp-login.php on line 349

Warning: Cannot modify header information – headers already sent by (output started at /home/design/public_html/wp-config.php:1) in /home/design/public_html/wp-includes/pluggable.php on line 690

etc. etc. etc.

thats as far as i can get! someone please help!! what am i doing wrong?