for($i =0; $i<sizeof($tmp);$i++) {
q = $q."INSERT INTO interest_answer (user_id, question, answer)
VALUES (".$db->quote($user_id).", ".$db->quote($question).",
".$db->quote($tmp[$i+1]).");
";
}
Du muss quotation-marks um deine values machen wenn's strings sind.
for($i =0; $i<sizeof($tmp);$i++) {
q = $q."INSERT INTO interest_answer (user_id, question, answer)
VALUES (".$db->quote($user_id).", '".$db->quote($question)."',
'".$db->quote($tmp[$i+1])."');
";
}