After I install wp-cache(manually, chmod to 777, asked web host to create the symbolic link, activate, edit wp-config.php by adding a line of command), my admin section started to be flooded by
Warning: Cannot modify header information - headers already sent by (output started at public_html/wordpress/wp-config.php:26) in public_html/wordpress/wp-includes/pluggable.php on line 331
Warning: Cannot modify header information - headers already sent by (output started at public_html/wordpress/wp-config.php:26) in public_html/wordpress/wp-includes/pluggable.php on line 331
These error are displayed every time I do something - eg. upload a photo, edit a post, activate/deactivate a plugin and etc. What does it mean?