Here's something that might help. Not sure. I just received the error log from BPS security. (I am definitely not adept at reading these things). I got more than 200 errors like this yesterday. With about 15 in the course of one minute.
Here is what it said (without the top part that says my ip address):
HTTP_REFERER: http://lucifit.com/wp-admi/admin.php?page=WordfenceSecOpt
REQUEST_URI: /wp-admin/admin-ajax.php
QUERY_STRING:
HTTP_USER_AGENT: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:27.0) Gecko/20100101 Firefox/27.0