Ajax modal won't work #13

jQuery("myElement").addEvent("click", function(){
id = jQuery(this).attr('rel');
var SM = new SimpleModal({"width":600});

  SM.addButton("Cancel", "btn");
  SM.show({
    "model":"modal-ajax",
    "title":"Title",
    "param":{
      "url":"http://mysite.com/bla/"+id
    }
  });

});

I get rel attribute (post numbers from my blog) and then add obtained id to the url of handler page. "Loading failed"...