Invalid Data: Please go back and try again.

This was reported a couple of month back, but I am having that same problem with WP 3.2.1 and WP Captcha-Free 0.8. Applied the ‘fix’ that was reported in the other thread (https://www.ads-software.com/support/topic/plugin-wp-captcha-free-invalid-data-please-go-back-and-try-again), but with no success.