Which frame the MovieClip is currently displaying

Howdy!

I have a MovieClip ("PlanRightPopoutMenu_mc") with two framesets labelled ("closed" & "opened"); I've been trying to add some code to a button that will check which frame the MovieClip is currently displaying...

on(release) {
if (_root.Plan_mc.PlanContent.PlanRightPopoutMenu_mc._currentframe == ("closed")) {
_root.Plan_mc.PlanContent.PlanRightPopoutMenu_mc.gotoAndStop("opened");
} else if (_root.Plan_mc.PlanContent.PlanRightPopoutMenu_mc._currentframe == ("opened")) {
_root.root.Plan_mc.PlanContent.PlanRightPopoutMenu_mc.gotoAndStop("closed");
}
}

Doesn't work : (

Can someone point out what I'm doing wrong as something like this would appear to be very simple.....thanks!!

Phill