Hello, sorry my english is'nt good...
Well, i don´t know it's a bug because i downloaded Moodle Beta 1.2 two weeks ago...
Inside graph.php file, when we use case "question.png" i found:
switch ($type) {
case "question.png":
$question = get_record("survey_questions", "id", $sid);
it is'nt $sid, it's $qid because when $sid it is used only when we need referer users...
Bye...