Nested movie clip not looping

Using Flash 8, I am creating a mp3 player that gets info from an external XML file. I am trying to create a masked scrolling message that gets the text data from the XML file. I have succeeded doing this and was very happy until I found out the message only scrolls once. I do not understand why it doesn’t loop.

The message is loaded into a movie clip inside the main timeline called prompt_mc that has a dynamic text field named prompt_txt inside of it. In prompt_mc I moved the message across 200 frames from right to left and then I dropped the prompt_mc on the main timeline with a mask object above it. The mask is handled in the code and works great. Anyone know why my prompt_mc is not looping or have any ideas??

Here is part of my code if it’s helpful:

// function to check if XML file is loaded and parse XML file
function loadXML(loaded) {
if (loaded) {
_root.prompt = this.firstChild.childNodes[1].firstChild.nodeValue;
_root.songtitleone = this.firstChild.childNodes[2].childNodes[0].firstChild.nodeValue;
_root.artistfirstSong = this.firstChild.childNodes[2].childNodes[1].firstChild.nodeValue;

prompt_mc.prompt_txt.text = _root.prompt;
songtitleone_txt.text = _root.songtitleone;

// prompt message mask
prompt_mc.setMask(mask_mc);

// play songs
var artistSong:String = _root.artistfirstSong;

controller.autoPlay = false;

play_mc.onRelease=function() {
if (this._currentframe == 1) {
this.gotoAndStop(“stop”);
controller.setMedia(artistSong,“MP3”);
controller.play();
}
else {
this.gotoAndStop(“play”);
controller.stop();
}
}

} else {
trace(“Error: file not loaded!”);
}
}

// load XML file and define XML object
xmlData = new XML();
xmlData.ignoreWhite = true;
xmlData.onLoad = loadXML;
xmlData.load(playlist_URL+name_URL+identity_URL);