PHP - Sql Error On Multi-page Order Script (using Session).

<form id="page1" method="post" action="calculator_q2.php">
<h1>1. Which best describes the primary and secondary sports combination that will be played on your pitch?</h1>
<table>
<tr><td>Rugby only</td><td><input type="radio" name="1_primary_secondary_combo" value="Rugby only"></td></tr>
<tr><td>Rugby/Soccer</td><td><input type="radio" name="1_primary_secondary_combo" value="Rugby Soccer"></td></tr>
<tr><td>Soccer/Hockey</td><td><input type="radio" name="1_primary_secondary_combo" value="Soccer Hockey"></td></tr>
</table>
<input class="blue" type="submit" value="Next">
</form>

<?php
 
	//Start the session
	session_start();		 
						 
	//Store our posted values in the session variables
	$_SESSION['1_primary_secondary_combo'] = $_POST['1_primary_secondary_combo'];					 
	
?>
<?php
	$debug=True;
	if ($debug) {
		echo ("Debug: session for q1 = ".$_SESSION['1_primary_secondary_combo']);
	}
?>
<form id="page2" method="post" action="calculator_q3.php">
<h1>2. Please choose a preferred surface</h1>
<table>
<tr><td>3G Rubber Crumb Filled Turf</td><td><input type="radio" name="2_preferred_surface" value="3G Rubber Crumb Filled Turf "></td></tr>
<tr><td>Sand Filled Turf</td><td><input type="radio" name="2_preferred_surface" value="Sand Filled Turf"></td></tr>
<tr><td>Sand Dressed Turf or<br>a Water Based Surface</td><td><input type="radio" name="2_preferred_surface" value="Sand Dressed Turf or a Water Based Surface"></td></tr>
</table>
							
<p>

<script>
function submitForm(action){
	document.getElementById('page2').action = action;
	document.getElementById('page2').submit();
}
</script>


<input class="blue" type="button" onclick="submitForm('/calculator_q1.php')" value="Previous" />
<input class="blue" type="button" onclick="submitForm('/calculator_q3.php')" value="Next" />
						
</form>

<?php
 
	//Start the session
	session_start();		 
						 
	//Store our posted values in the session variables
	$_SESSION['2_preferred_surface'] = $_POST['2_preferred_surface'];

?>
<?php
$debug=True;
if ($debug) {
	echo ("Debug: session for q1 = ".$_SESSION['1_primary_secondary_combo']);
	echo ("<br>Debug: session for q2 = ".$_SESSION['2_preferred_surface']);
}
?>

<form id="page3" method="post" action="calculator_q4.php">
<h1>3. Please choose one watering option</h1>
<table>
<tr><td>With a Rain Gun System</td><td><input type="radio" name="3_watering_option" value="With a Rain Gun System"></td></tr>
<tr><td>With a Rain gun System + Water Borehole</td><td><input type="radio" name="3_watering_option" value="With a Rain gun System + Water Borehole"></td></tr>
<tr><td>Not Required</td><td><input type="radio" name="3_watering_option" value="Not Required"></td></tr>							
</table>					
<p>
						
<script>
function submitForm(action){
	document.getElementById('page3').action = action;
	document.getElementById('page3').submit();
}
</script>

	<input class="blue" type="button" onclick="submitForm('/calculator_q2.php')" value="Previous" />
	<input class="blue" type="button" onclick="submitForm('/calculator_q4.php')" value="Next" />
</form>

<div class="new-store-container" id="new-store-container" name="new-store-container" style="display:none;">
    <div class="control-group">
        <div class="other-store" id="new_store_name">
            <?php echo standardInputField('New Store Name', 'new_store_name', '', $errors); ?>
        </div>
    </div>
</div>

<select class="store-name" name="store_id" id="store_id" onclick="toggle_visibility('store_id','new-store-container')">
    <?php echo $store_options; ?>
                            
    <?php
        if($values['store_id'] == "OTH")
            {
                echo "<option value='OTH' selected> <<<--- NEW STORE --->>> </option>";
            }
        else
            {
                echo '<OPTION VALUE="OTH"> <<<--- NEW STORE --->>> </OPTION>';
            }
    ?>
</select>

function toggle_visibility(fieldName, containerName)
{
    var e = document.getElementById(fieldName);
    var g = document.getElementById(containerName);
            
    if (e.value == 'OTH')
        {
            if(g.style.display == 'none')
                g.style.display = 'block';
            else
                g.style.display = 'none';
        }
}

<script src="//ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.js"></script>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<script>
$( document ).ready(function() {
	
	var files       = $('.input-file').prop("files");
	var file_count  = files.length;
	
	var names = $.map(files, function(val) { 
		return val.name; 
	});
	
	$('#input-file-button').click(function() {
		$('.input-file').click(); 
	});
	
	$('.input-file').change(function (){
		var file_name = $(this).val();
		var file_path = URL.createObjectURL(event.target.files[0]);

		$('#uploaded-images').append('<div><img src="'+ file_path +'" /></div>' + file_name);	
	 });
		
	if (file_count < 1)
	{
		$('#uploaded-images').text("No images are selected.");
	}
});


</script>
<style>
.input-file
{
	display: none;
}
</style>
</head>
<body>
<div id="uploaded-images"></div>
<br />
<input type="file" name="files[]" class="input-file"/><span id='input-file-button'>Upload Photo</span>
</body>
</html>