after download this plugin my admin panel every time show me this problem:

Warning: Cannot modify header information – headers already sent by (output started at /var/www/admin/www/designersfromrussia.ru/wp-content/plugins/includer/includer.php:3) in /var/www/admin/www/designersfromrussia.ru/wp-content/plugins/post-views-counter/includes/counter.php on line 297

I don’t now how i can returner all(
And used my website again!