change movieclip alpha based on xml variable

[cr84net2]

I have an swf that plays a video (toobplayer component) and has two dynamic txt fields. The video and both txt fields are "fed" from an xml file. I also have a movie clip that loads an image on another layer and is set to an alpha of 0. Is there a way to use a conditional statement to check the video variable and if one is not present to change the image loading movieclip to an alpha of 100. here is what I am working with.

var configXML:XML = new XML();

loadConfig = function(xmlFile:String) {
  var scope = this;
  
  configXML.ignoreWhite = true;
  configXML.load(xmlFile);
  configXML.onLoad = function(success) {
    if(success) {
      scope.initApplication();
    } else {
      trace("Error loading XML file ("+xmlFile+")");
    }
  }
}

getConfigParam = function(param:String) {
  var tmp = configXML["idMap"][param];
  if(tmp == undefined) {
    tmp = this[param];
  } else {
		tmp = tmp.attributes["value"];
	}
  return tmp;
}

initApplication = function() {
	var tagName2:String = getConfigParam("tagName2");
	var tagCon2:String = getConfigParam("tagCon2");
    var vidpath = getConfigParam("videoFile2");
	var imgName1:String = getConfigParam("imgName1");
	imgName_mc._target= imgName1;
	tagName_txt.htmlText = tagName2;
	tagCon_txt.htmlText = tagCon2;
	videoPlayer_vid.url = vidpath;
	  loadVideo();
  
}



loadVideo = function() {
  var vid_nc:NetConnection = new NetConnection();
  vid_nc.connect(null);
  var vid_ns:NetStream = new NetStream(vid_nc);
  videoPlayer_vid.attachVideo(vid_ns);
  vid_ns.play(getConfigParam("videoFile2"));
}

If (vidpath.value == undefined); {

	imgName_mc.alpha= 100;
	loadClip();
}

loadConfig("xml/config.xml");

The video and dynamic text fields work fine as long parameters are available in the xml. However i am not having any luck with changing the alpha of the image movie clip if no video parameters are avaiable. i have tried

return (vidpath.length > 0); Then setting the alpha to 100
Also
return (vidpath.value == 0); Then setting the alpha to 100

without any luck. I am using Flash 8 and do not have much experience with it. I have been reading and trying different methods to get here.

Any help would be appreciated.