Access to restricted URI denied" code: "1012 [Break On This Error]

xhttp.send(null);

function getXML(xml_file) {

  

  if (window.XMLHttpRequest) {

    

    var xhttp = new XMLHttpRequest();  // Cretes a instantce of XMLHttpRequest object

  }

  else {

    

    var xhttp = new ActiveXObject("Microsoft.XMLHTTP");  // for IE 5/6

  }

  

  xhttp.open("GET",xml_file,false);  

  xhttp.send(null);  

  

   var xmlDoc = xhttp.responseXML; 

 

   return (xmlDoc);

}

I'm trying to get data from a XML file using JavaScript. Im using Firebug to test and debug on Firefox.

The above error is what I'm getting. It works in other places i used the same before, why is acting weird here?

Can someone help me why it's occuring?

Update:

http://jquery-howto.blogspot.com/2008/12/access-to-restricted-uri-denied-code.html

I found this link explaining the cause of the problem. But I didn't get what the solution given means can someone elaborate?