Global Variable Help

I’ve been trying for a while to set a global variable from an xml file within a function and then be able to use it in another function. Any help would be appreciated.

function loadXML(loaded) {
	if (loaded) {
		_global.columns = this.firstChild.firstChild.firstChild;
		xmlNode = this.firstChild.nextSibling;
		image = [];
		description = [];
		thumbnails = [];
		total = xmlNode.childNodes.length;
		for (i=0; i<total; i++) {
			image* = xmlNode.childNodes*.childNodes[0].firstChild.nodeValue;
			description* = xmlNode.childNodes*.childNodes[1].firstChild.nodeValue;
			thumbnails* = xmlNode.childNodes*.childNodes[2].firstChild.nodeValue;
			thumbnails_fn(i);
		}		
		firstImage();
	} else {
		content = "file not loaded!";
	}
}

xmlData = new XML();
xmlData.ignoreWhite = true;
xmlData.onLoad = loadXML;
xmlData.load("images.xml");

previous_btn.onRelease = function() {
	prevImage();
};

next_btn.onRelease = function() {
	nextImage();
};

p = 0;

this.onEnterFrame = function() {
	filesize = picture.getBytesTotal();
	loaded = picture.getBytesLoaded();
	preloader._visible = true;
	if (loaded != filesize) {
		preloader.preload_bar._xscale = 100*loaded/filesize;
	} else {
		preloader._visible = false;
		if (picture._alpha<100) {
			picture._alpha += 10;
		}
	}
};

function nextImage() {
	if (p<(total-1)) {
		p++;
		if (loaded == filesize) {
			picture._alpha = 0;
			picture.loadMovie(image[p], 1);
			desc_txt.text = description[p];
			picture_num();
		}
	}
}

function prevImage() {
	if (p>0) {
		p--;
		picture._alpha = 0;
		picture.loadMovie(image[p], 1);
		desc_txt.text = description[p];
		picture_num();
	}
}

function firstImage() {
	if (loaded == filesize) {
		picture._alpha = 0;
		picture.loadMovie(image[0], 1);
		desc_txt.text = description[0];
		picture_num();
	}
}

function picture_num() {
	current_pos = p+1;
	pos_txt.text = current_pos+" / "+total;
}

thumb_spacing = 110;

function thumbnails_fn(k) {
	thumbnail_mc.createEmptyMovieClip("t"+k, thumbnail_mc.getNextHighestDepth());
	tlistener = new Object();
	tlistener.onLoadInit = function(target_mc) {
		target_mc._x = (k%columns)*thumb_spacing;
		target_mc._y = Math.floor(k/columns)*80;
		//target_mc._x = (target_mc._width+thumb_spacing)*k;
		target_mc.pictureValue = k;
		target_mc.onRelease = function() {
			p = this.pictureValue-1;
			nextImage();
		};
		target_mc.onRollOver = function() {
			this._alpha = 50;
		};
		target_mc.onRollOut = function() {
			this._alpha = 100;
		};
	};
	image_mcl = new MovieClipLoader();
	image_mcl.addListener(tlistener);
	image_mcl.loadClip(thumbnails[k], "thumbnail_mc.t"+k);
}

-Thanks-
Saveth