[jQuery] jQuery.ajax form submission to MySQL

[spstieng]

Hi guys.
I'm using Wordpress CMS where I have created a custom form. I would
like to store the input from this form in a database (MySQL).

I've posted my problem here: 
http://stackoverflow.com/questions/852054/store-form-data-in-mysql-with-jquery-ajax
, but I think maybe this forum is a better place for mye problem.

I have the following script:
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: "../includes/storelocator/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;
  });
}

Firebug is reporting a 404 Not Found. I've tried several different
paths in the url property. But no mather what, it can't locate the
process_frm_store.php.

The error message is also triggered, but that only says 'Undefined' -
I have no idea what that means.