Parameter url must be non-null

i am getting the Parameter url must be non-null error while trying to pass the path of an XML file to an Shockwave flash object.

The javascript code is as follows

<script type="text/javascript">
    var so = new SWFObject("preview.swf", "", "100%", "100%", "9", "#ffffff");
    so.addParam("allowFullScreen", "true");
    so.addParam("scale", "noscale");
    so.addParam("menu", "false");
    so.addVariable("xmlPath", "xml/exampleData.xml");
    so.write("flashcontent");
</script>

As you can see the XML file i am trying to load within the SWF file is the exampleData.xml

Within the ActionScript i declared the variable xmlPath as follows...

 public var xmlPath:String

and in the load event i made the appropriate changes

private function loadComp(data:String):void
        {
            xmlModel.xml = new XML(data);
            new LoadXml(xmlPath, picHandler);
        }

And here comes the question.

What am i doing wrong here? Why do i get the Parameter url must be non-null error?

P.S. If i hard-code the path, within the actionscript file开发者_开发百科, everything works great!

private function loadComp(data:String):void
        {
            xmlModel.xml = new XML(data);
            new LoadXml('xml/exampleData', picHandler);
        }

---

I usually do this kind of thing with a flashvar parameter in the embed code.

   so.addParam('flashvars','xmlPath=xml/exampleData.xml');

And then you'll need a line like this in your Actionscript...

   private var xmlPath:string;
   xmlPath = root.loaderInfo.parameters.xmlPath;