I saw that you have an error in your form code... you wrote
<form name= "questionnaire" form method="post" action="<?php echo $PHP_SELF;?>">
and its
<form name="questionnaire" method="post" action="<?php echo $PHP_SELF;?>">
You wrote a form when another form was already at the begining... i mean, you opend tag, but then there is another form and then method... try now !!