Problem sending variables that are in an MC

I make student exercises that are submitted to instructors. They are usually straight-forward. Just input boxes on the main stage and I submit them using this code:

on (release) {
subject=“Forms”;
next_url="/all/submitted.html";
getURL("/cgi-bin/mail?fs", “_self”, “POST”);
}

However, I’ve had to make a more complicated form that is inside a movie clip. The vars inside the MC don’t send.

So I tried setting another variable on the _root equal to the input box instance names

var casename_ipt:String;
_root.casename_ipt = _root.nagivationpane.container.form74.casename.text;

Still no dice. The variables that are on the _root all send, but the ones in the MC(form74) still don’t. Anyone know how I can get around this problem?