Not importing

Not importing. States next scheduled import date is 1969 at 7pm. When forced, we receive the following – Warning: Cannot modify header information – headers already sent by (output started at /home/content/98/6615198/html/wp-admin/includes/template.php:1642) in /home/content/98/6615198/html/wp-content/plugins/jetpack/modules/subscriptions.php on line 502

http://wordpress.org/extend/plugins/facebook-comments-importer/