dont allow "not trusted" bots...and remove your general "searchbot" acount. create for each "known" bot an independent account, like google, msn, yahoo, etc. this way you can track them down.
And finaly the real fix:
in details.php find:if ($row['image_allow_comments'] == 0 || !check_permission("auth_postcomment", $row['cat_id']) || !$row) {
Replace with:if ($user_bot || $row['image_allow_comments'] == 0 || !check_permission("auth_postcomment", $row['cat_id']) || !$row) {
That should be enough, yet, if you also dont want to show comment form for the bots, then find:$allow_posting = check_permission("auth_postcomment", $cat_id);
Replace with:$allow_posting = (!$user_bot && check_permission("auth_postcomment", $cat_id)) ? 1 : 0;