PHP :: Multiple Image Uploader Not Working

I'm attempting to create a multiple image uploader (think Coppermine) where the user clicks a button in an SWF, selects a file or multiple files, and then these files are uploaded to a directory. I have a PHP script that handles the uploading a file, and my Flash file iterates over the files in the FileReferenceList and sends the file to this PHP script to upload. The directory path in the PHP script is correct, and permissions set to 777.

The contents of my ActionScript 3.0 class look like this:
package com.yourfightsite.imageupload {
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.IOErrorEvent;
import flash.events.MouseEvent;
[Code] .....

The three methods at the bottom of the class fire JavaScript functions in my HTML page that add the file names to a file queue widget, and update the percent value next to them, and finally mark them as complete. However, when I select files, they are added to the file queue widget as expected and then nothing. The files aren't uploaded, the files in the file queue widget aren't updated, and no errors are thrown, either in the console (I'm using Chrome) or Flash when publishing my movie.