word list captcha "not working"

Did you try to answer to the CAPTCHA as untrusted user yet?
This is expected to fail most of the times if I recall correctly.

The problem is situated (and documented) in word_list_captcha.module:

$captcha['form']['captcha_response'] = array(
          '#type' => 'radios',
          '#title' => t('Which word does not belong to the list?'),
          '#options' => $options,
          // extra class needed for additional CSS'ing of the options
          '#attributes' => array('class' => 'text-captcha-word-list-radios'),
          // TODO: the following needs to be ported to Drupal 6, which does not
          // support DANGEROUS_SKIP_CHECK anymore
          //
          // The following entry '#DANGEROUS_SKIP_CHECK' is needed to prevent
          // that Drupal checks during validation phase if a submitted option
          // is in the list of possible options. (see includes/form.inc)
          // The options are randomly generated on each call and consequently
          // almost never the same during the generate phase and the validation
          // phase.
          '#DANGEROUS_SKIP_CHECK' => TRUE, //
          '#required' => TRUE,
        );

I'm closing it because the issue was created a long time ago without any further steps.

if you still need it then raise a new one.
thanks