getting an error in error_log in root of WP Site moderation.php on line 663

Getting this same error a few times now since last log delete this is the only type of error thats happening, for the dates of 18th, 21st,and this one yesterday.
Not sure whats causing it. I have no errors from the front end.
no error in the cpanel error log
[22-Sep-2013 04:08:17 UTC] PHP Warning: Invalid argument supplied for foreach() in /home/XXXX/public_html/wp-content/plugins/moderation/moderation.php on line 663