I am trying to install and activate some plugins on my new site: http://justice-liberty.com/wordpress/. But while trying activate some of them, I get messages like this:
Warning: Cannot modify header information - headers already sent by (output started at /home/content/j/u/s/justliberty/html/wordpress/wp-content/plugins/wp-ad-gallery/wp-ad-gallery.php:177) in /home/content/j/u/s/justliberty/html/wordpress/wp-includes/functions.php on line 862
And it's not activated.
Can you explain this?