Undefined AJAX error

I had to come here to see if anyone has ever had an error where there isn't on开发者_运维技巧e in JQuery AJAX.

I am returning xml and it all works fine on one server but not on another. The response code in Firebug is 404 but when I open it up both the response and xml are showing my xml. The success is not firing, and the error is showing as undefined.

The working version is here http://www.write-about-property.com/test/

and the unworking is here http://ukfloorsanding.com/

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Ajax.php does not exist on the not working website.