@epilot, got your link. The captcha displayed looks like the older version. I was able to (I think) send you a test message, did you receive it?

Are you sure that you removed/replaced all the older captcha files with the updated version?

Regarding the debug-logs, find one that identifies an issue with the captcha and post its contents here, in the support thread, using "CODE" tags (the big # in the menu-bar when you write your reply).