(I've boiled my problem down to a simple example):
with AS3, I try to load a PHP file which is stored on my server (code below).
This PHP file only does one thing: echo a string.

When I compile my flash file: the loader finishes, and I see the echoed string.
But, when I copy this exact flash file to my server: the loader never seems to finish. I never see the echoed string.

(+ I'm appending strings to a dynamic textBox on the stage. Sort of like tracing every step of my progress. No further strings appear after I load, so I assume this where it is dying.)

MY GUESS: this must be some sort of permissions problem. Like maybe the server won't let some (flash) files call other (php) files? (permissions are rw-rw---- ... but temporarily changing to rwxrwxrwx didn't seem to help). Snarky tech friends assure me the problem must be in my code.
(I'm definitely out of my depth).

help?

----------------PHP FILE CODE:
<?php
header('Content-Type: text/html; charset=utf-8');
echo("youAccessedME...");
?>


----------------PHP FILE CODE:
package {
import fl.controls.*;
import flash.display.*;
import flash.events.*;
import flash.text.*;
import flash.net.*;

public class testingPHP extends MovieClip{
public function testingPHP() {
st_SaveData.addEventListener(MouseEvent.CLICK, saveGame); //when button clicked...
var tf_StatsPop:TextFormat = new TextFormat();
tf_StatsPop.font = "Arial";
stDBecho.defaultTextFormat = tf_StatsPop;
stDBecho.text = "welcome. ";
}
public function saveGame(evt:Event):void{ //submit button has been clicked.
stDBecho.text = "saving: ";
var myPrequest:URLRequest = new URLRequest();
myPrequest.url = "http://www.oregonstate.edu/instruct/dce/css440/MemoryTool/test.php";
var loader:URLLoader = new URLLoader();
loader.load(myPrequest); //sends the request
loader.addEventListener(Event.COMPLETE, storeToServerLAST);
}
public function storeToServerLAST(evt:Event):void{
stDBecho.appendText(". entered final stage. ");
stDBecho.appendText(". End result:" + evt.target.data);
}
}
}