I got in once with TOR, clicked a forum link and waddya know: same issue.
At least that time I could actually see the captcha popupwindow, but it kept failing no matter how I clicked it.
Verify that you are human
This action was flagged as risky. Complete the configured CAPTCHA check to continue. Normal trusted users should not be challenged constantly.
This is the message i get as well, and i run no scripts or addons. I get IP-banned for being a bot for a while, then I can...