what $.ajax error happened?

what $.ajax error happened?

Hi,

I have an ajax request as following:

$.ajax({
      type: 'POST',
      url: 'link',
      success: function(xml, status, request) { alert("success"); },
      error: function(request, status, error) { alert(status); alert(error); }});

The request always return as an error (the error handling function is always called) and I get "error" for status and "undefined" for error. Could you guys please let me know what possibly be wrong with the request? The url is a fully qualified url that returns an xml (I have tested the url in web browser and it works fine).

Thank you very much.