If the above cannot work at your end for some reasons, please give a simple solution to stem BOT activities as per screenshot below some logical thoughts of what is really your need.
Google currently has 3 versions of Captcha. Phprunner uses version 2, but the link on the Phprunner site, Google has redirected to their new corporate enterprise Captcha which is incompatible with Phprunner.
After a lot of research I found version 3 of Captcha which also doesnt work. And it worked when I tried version 2. Google tries really hard to redirect all Captcha queries to their new enterprise version.