This error in Firefox

XML Parsing Error: no element found Location: moz-nullprincipal:{dd117028-da50-7b48-9a90-51f90c48ea9e} Line Number 1, Column 1

was seen on a xml get request using jQuery’s ajax function in this manner:

$.ajax({
        type: "GET",
        url: "myxml.xml", 
        dataType: "xml",
        success: myCompleteFunction,
        complete: mySuccessFunction,
        failure: function(data) {
            alert("Problem getting XML");
            }
    });

The fix was making sure the XML was valid and changing the dataType to html.

$.ajax({
        type: "GET",
        url: "myxml.xml", 
        dataType: "html",
        success: myCompleteFunction,
        complete: mySuccessFunction,
        failure: function(data) {
            alert("Problem getting XML");
            }
    });

By the way, the ajax request to get an xml file may also fail if the xml file is located on another domain. No fix if that is the case.