Hi,
Thanks for the quick reply. Sorry, I have made a typographic error above. The Wordfence version already IS 6.0.7. And the PHP Version is 5.5.24.
The problem is now resolved. It seems the problem arose from an unagreeable IP range in the ‘Whitelisted IP addresses that bypass all rules’ field. I have cleared the field and as a result cleared the error. I guess I had either declared the IP range incorrectly or my IP address has changed.
Thanks.