Firebug shows POST info, but I can't echo - php

Question

I have a form that seems to POST successfully after submitting via AJAX. Under "NET" in Firebug the posted info displays properly. But I cannot echo this data at all.
I'm trying this, which is the 1st field in my form: <?php echo $_POST['sun_exposure']; ?>
Does this have anything to do with the form's ACTION not having a url?
Also, I'm trying to POST data to the same page, and not a PHP file. Maybe this is part of the problem? This is also a Wordpress page, and not a file.
Here's the live url: http://www.richmindonline.com/container-creations/personal-creations-assistant/
Here's the form code:
<form id="quotation_form" name="vdmQuotationForm" action="#" method="post">
<div id="page1">
<div id="step0_header" class="steps-headers" onClick="step0ToggleClick();">Step 1<span style="margin-left:30px;">Sun Exposure</span></div>
<div id="step0" class="quotation-steps"><strong>Describe the sun exposure of your planter...</strong><br/>
<div class="radio-container"><input onchange="go_to_next_step();" type="radio" name="sun_exposure[]" id="full_sun" value="Full Sun"<?php checked( 'Full Sun',$_POST['sun_exposure[]']); ?> /><label class="label-quotation-steps">Full Sun</label><br class="clear"/></div>
<div class="radio-container"><input onchange="go_to_next_step();" type="radio" name="sun_exposure[]" id="part_sun" value="Part Sun"<?php checked( 'Part Sun',$_POST['sun_exposure[]']); ?> /><label class="label-quotation-steps">Part Sun</label><br class="clear"/></div>
<div class="radio-container"><input onchange="go_to_next_step();" type="radio" name="sun_exposure[]" id="full_shade" value="Full Shade"<?php checked( 'Full Shade',$_POST['sun_exposure[]']); ?> /><label class="label-quotation-steps">Full Shade</label><br class="clear"/></div>
</div>
</div>
</div>
</form>
Here's the AJAX request, which is wrapped up in the jQuery validate script:
<script type="text/javascript">
jQuery(document).ready(function($) {
$('#quotation_form').validate({ // initialize the plugin
rules: {
'sun_exposure[]': {
required: true,
},
'height[]': {
required:true,
},
'diameter[]': {
required:true,
},
'shape[]': {
required:true,
},
'placement[]': {
required:true,
},
},
messages: {
'sun_exposure[]': {
required: 'Please choose a sun exposure for your plant',
},
'height[]': {
required: 'Please choose the height of your planter'
},
'diameter[]': {
required: 'Please choose the diamter of your planter'
},
'shape[]': {
required: 'Please choose the shape of your planter'
},
'placement[]': {
required: 'Please choose the placement of your planter'
},
},
errorPlacement: function (error, element) {
alert(error.text());
},
submitHandler: function (form) { // for demo
alert('valid form submitted'); // for demo
var form_data = $("#quotation_form").serialize();
$.ajax({
url: "http://www.richmindonline.com/container-creations/personal-creations-assistant/",
type: 'POST',
data: form_data,
cache: true,
success: function(data) {
alert(data);
}
});
$('#page1').hide();
$('html, body').animate({ scrollTop: $('body').offset().top }, 10);
$('#page2').show();
$('.intro').hide();
$('.to_page1').show();
return false;
}
}); // end .validate()
});
</script>