cant get alpha

[camilogo1]

I can't seem to access the _alpha property of dynamically loaded movies. here's the code:

var roomsAR = new Array("board", "club", "hall", "lobster", "privDining", "normandie", "intro");
//fades mid and footer movies, makes button white
function fader (roomNum) {
for (var i = 0; i < 7; i++) {
roomMC = roomsAR[i]+"MC";
trace(roomMC);
roomInstance = roomMC+i;
_root.emptyMC.attachMovie(roomMC,roomInstance,i);
//_root.emptyMC._alpha = 0;
trace(roomInstance);
trace(_root.emptyMC.hallMC._alpha);
}
}

The alpha test appears as undefined every time. Help!

[red penguin]

attachMovie returns a reference to the attached clip!
Use that in the code:

var myClip:MovieClip = _root.emptyMC.attachMovie(roomMC,roomInstance,i);
myClip._alpha = 50;