CAPTCHA session reuse attack detected error message when form is submitted I am experiencing problems with the captcha module 7.x-1.0-beta1 version. I have enabled captcha in webforms for anonymous users. After submitting the form it repeatedly gives me the error message, 


  CAPTCHA session reuse attack detected


.. This happens for only one of the webform in which captcha is placed. I am using Drupal 7.2 version.

Any solution for this issue will be really helpful.
I had the same problem because I have an ajax file upload on the form. The solution is to patch the captcha module with the patch found here http://drupal.org/node/918856#comment-6353912 .
You just need to download the patch and put it in the same folder and run in command line: 

patch &lt; captcha-patch-10022012.patch


if using git, you can just use :

git apply --directory=your/module/derectory captcha-patch-10022012.patch