Movie clip losing variable value

[jgriffi]

I'm duplicating movie clips and during that process I'm setting a key number and a movieNumber that are on the timeline of the movie clip, then calling the setClipFunctions function below. When I pass the movieClip parameter to the function, the trace shows it picks up the key and movieNumber variable just fine, but when I click the Edit button,the trace shows the movieClip name but the key and movieNumber variables have set back to 0.

function setClipFunctions(a:MovieClip):Void {
	var thisClip:MovieClip = a;
	trace("this clip @ setClipFunctions = "+thisClip);
	trace("this key @ setClipFunctions = "+thisClip.key);
	trace("this movienumber @ setClipFunctions = "+thisClip.nMovieNumber);
....more code...
	//edit button
	thisClip.btEdit.onRelease = function() {
		trace("this clip @ btEdit = "+thisClip);
		trace("this key @ btEdit = "+thisClip.key);
		trace("this movienumber @ btEdit = "+thisClip.nMovieNumber);
		loadFormat(thisClip, thisClip.key, thisClip.nMovieNumber);
		thisClip._visible = false;
	};
}

The code in between just sets drag and drop parameters and a textbox, nothing that interferes with these two variables at all.
I don't understand how they have been reset or lost. Can anyone point out my error? I'm using Flash 8 and AS2

[jgriffi]

Sorry - worked it out! Had to put a bit of code in the MC to stop it resetting the variables:

if ((key == undefined) || (key == 0)) {
	var key:Number = 0;
} else {
	trace("key from within mc = "+key);
}
if ((nMovieNumber == undefined) || (nMovieNumber == 0)) {
	var nMovieNumber:Number = 0;
} else {
	trace("movieNumber from within mc = "+nMovieNumber);
}