comment error message

When people leave comments on my posts they always receive this error message:

Warning: Missing argument 2 for Endurance_Page_Cache::comment(), called in /home1/wordsbz6/public_html/wp-includes/class-wp-hook.php on line 300 and defined in /home1/wordsbz6/public_html/wp-content/mu-plugins/endurance-page-cache.php on line 167

Warning: Cannot modify header information – headers already sent by (output started at /home1/wordsbz6/public_html/wp-content/mu-plugins/endurance-page-cache.php:167) in /home1/wordsbz6/public_html/wp-includes/pluggable.php on line 1210

Please let me know how to fix this. Thanks!