Unable to activate the plugin

Installing the plugin throws this error message:

Warning: fopen(/home/wisdomad/public_html/demo.techmaaxxdemo.com/wp-content/plugins/buddypress/bp-loader.php): failed to open stream: No such file or directory in /home/wisdomad/public_html/demo.techmaaxxdemo.com/wp-includes/functions.php on line 5974

Warning: fread() expects parameter 1 to be resource, boolean given in /home/wisdomad/public_html/demo.techmaaxxdemo.com/wp-includes/functions.php on line 5977

Warning: fclose() expects parameter 1 to be resource, boolean given in /home/wisdomad/public_html/demo.techmaaxxdemo.com/wp-includes/functions.php on line 5980

Unable to activate the plugin also.