AlexPR on "[Plugin: W3 Total Cache] In Settings, message "Change the permissions back to the default" keeps staying"

I have changed the permissions back to the defaults using the command "# chmod 755 /var/www/wordpress/wp-content" but the message "/var/www/wordpress/wp-content is write-able. When finished installing the plugin, change the permissions back to the default: chmod 755 /var/www/wordpress/wp-content. Permissions are currently 777" does not disappear in the settings menu.
I have entered the command as specified in the installation guide and did not get any errors. What could have gone wrong? :-)

http://wordpress.org/plugins/w3-total-cache/