Store form data in MySQL with jQuery.ajax

Hi, I’m having problems processing a form so that I can save its data in my MySQL database. I’m using WordPress as CMS.

I’ve used this example: http://www.ryancoughlin.com/2008/11/04/use-jquery-to-submit-form

I’m pretty sure that the source of my problem is that I’m using the wrong url in the javascript. The error message only returns ‘undefined’ and Firebug reports a page not found 404 error.

So what would be the correct url?
Any help would be greatly appreciated.

This is my site structure:

Mywebsite (folder)      
  sl_register.tpl.php   
  includes    (folder)    
  storelocator (folder)
    process_frm_store.php
    frm_store.php
  js (folder)
    myscripts.js

And this is the logic of my site build up:

sl_register.tpl.php:

<?php
/*
  Template Name: SL - Register Store
*/  
  get_header();
  include_once 'includes/storeLocator/frm_store.php';
  get_footer();
?>

frm_store.php:

<form id="store_data_form" class="appnitro"  method="post" action="">
  <input id="store_active" name="store_active" type="hidden" value="pending" />
  <input id="store_name" name="store_name" type="text" value=""/> 
  <input id="store_street1" name="store_street1" type="text" value="" />
  <input id="saveForm" class="submitButton" type="submit" name="save" value="Save" />
</form>

process_frm_store.php:

<?php
  $myDB = new DAL(); 
  $myDB->connect();

  if (isset($_POST['save'])) 
  {
    $formData =  array(
      "name"=> mysql_real_escape_string($_POST['store_name']),
      "street1"=> mysql_real_escape_string($_POST['store_street1']),
      "zipcode"=> mysql_real_escape_string($_POST['store_zipcode']));

    $myDB->addNewStore($formData);
  }
?>

myscripts.js:

jQuery.processForms = function()
{
  jQuery('form#store_data_form').submit(function() 
  {
    var store_name = 'Test store'; //jQuery("input#store_name").val();
    var store_street1 = 'Sesamy street';//Set constant for testing
    var store_zipcode = '0574'; //Set constant for testing
    var dataString = 'name='+ store_name + '&street1=' + store_street1 + '&zipcode=' + store_zipcode;    
    jQuery.ajax(
    {   
      type: "POST",   
      url: "process_frm_store.php",   
      data: dataString,
      error: function(XMLHttpRequest, textStatus, errorThrown) 
      { 
        alert(errorThrown); // Just for debugging
        jQuery('#suggestNewStore div.error').fadeIn(); 
      },
      success: function() 
      {
        alert('It works!');
        jQuery('#suggestNewStore div.success').fadeIn();   
      }   
    });   
    return false;      
  });
}