Replacing Remote XML with Local

In my html, I have

var frank = "";
        flashvars.john = frank;

and relating to this in my swf i have

var theXML = new XML();
theXML.ignoreWhite = true;
theXML.onLoad = function (success)

when i remove the code from my html, and replace ‘john’ with “myXML.xml”, which directs to a local file, all my dynamic text boxes become undefined, even though it is linking to an identical xml, its just local and not on the internet. anyone know why this could be?