Code problem, making Mc play

Hi, im having problems executing correct action script. Im using movie clips and when using buttons under them everything works fine. Im putting the script in the maintimeline: code below:

e.g
_root.mainMenu.floor1_btn.onRelease = function () {
loadMovie (“comingsoon.swf” , “membersOnly”);
};

Now what i want to do is when the timeline gets to say frame 200, ive an action waiting to play a movie clip (instance “liftMc”) but i can’t seem to get it to play?

i’ve tried writing a function as well as modifying the script above but i can never get it to play? hope someone can help please, i know this is basic stuff but i’ve been on it for hours. Beginners Eh!

cheers dave