Cannot modify header information – headers already sent by ERROR

This is a fresh install. My problem is that whenever I try to log in I get the following messages:

Warning: Cannot modify header information – headers already sent by (output started at /home/farms/www/wp-config.php:1) in /home/farms/www/wp-login.php on line 390
Warning: Cannot modify header information – headers already sent by (output started at /home/farms/www/wp-config.php:1) in /home/farms/www/wp-login.php on line 403

Also, I get the following messages above the login fields:

ERRO: Os cookies est?o bloqueados devido a um resultado inesperado. Para obter ajuda, consulte esta documenta??o ou tente o fórum de suporte.

I have already searched the foruns extensivelly and it seams that the problem is with the line 1 of wp-config, which is affecting lines 390 and 403 from wp_login.

This is what I have already tried, without sucess:

– Activate cookies
– Clean browser cache
– Clean computer cache
– Use another browser
– reintall wordpress
– install previous versions of wordpress
– checking if there are empty spaces before <?php or after ?> in every php file, but, maninly in wp_config
– Chech if every php file has ?> as closure
– Check for empty spaces in functions.php
– Desactivate plugins

I don’t know what to do anymore. I have already tried every of the above suggestions and none works. Any idea?