Column 'nid' in on clause is ambiguous query

Drupal version 6.19
PhP version 5.1.14
MySQL version 4.1.22

I installed Quiz 6.x-4.0-rc8

Without changing any of the default settings, I created a basic Short Answer quiz, with 5 questions.

After taking the quiz, the following error message appears:

user warning: Column 'nid' in on clause is ambiguous query: SELECT question_nid, question_vid, type, rs.max_score FROM quiz_node_results_answers ra LEFT JOIN node n ON (question_nid = nid) LEFT JOIN quiz_node_results r ON (ra.result_id = r.result_id) LEFT OUTER JOIN quiz_node_relationship rs ON (question_vid = rs.child_vid) AND rs.parent_vid = r.vid WHERE ra.result_id = 1 ORDER BY answer_timestamp in /sites/all/modules/quiz/quiz.module on line 3138.

Additional information: I did experiment with Quiz version 3, but I uninstalled it some time ago. I thought I cleaned out all remnants, but I may have missed something.

This is the second time I tried Quiz 4.0-rc8. I installed it a few weeks ago, and experienced exactly the same problem. so I uninstalled the module, and tried to delete every remnant. But again, I may have missed something.

Below the error message, I can see my scores, but I nothing appears under the heading "Question Results". I intentionally got 1 question wrong, so I think I should see the correct answer there.

I need the module for my elearning site. I have searched the forums, but found nothing.

I have no idea how to address this. My knowledge of programming is minimal, although I can follow instructions.

Please give me guidance.

Thanks you.