Passed variables Flash -> PHP are empty

Hello!

I'm having problems with the upload section of my website.
People can enter the details of a song and upload it.
When it is uploading, a file called appenlist will send the variables to my xmlplaylist.
But when i check my playlist afterwards, the variables are empty.

This is my AS2 code

Actionscript Code:

lvSend = new LoadVars();
lvSend.titel = tTitel.text;
lvSend.artist = tArtist.text;
lvSend.genre = tGenre.getValue();
lvSend.name = file.name;
lvSend.sendAndLoad("appendlist.php", lvReceive, "POST");

The added text in my xml playlist looks like this:

Actionscript Code:

<listitem name='' - ''>
<stream name=''>
</listitem>

Instead of the variables it gives nothing.

My code for receiving the variables in php is this:

Actionscript Code:

$titel = $_POST['titel'];
$artist = $_POST['artist'];
$genre = $_POST['genre'];
$name = $_POST['name'];

Why are my variables empty? Did something went wrong while passing the variables?

I'm using WampServer to host my site locally.

Any help is appreciated!
Hendrik-Jan