Simple movie clip issue

anybody could help…

I can not find the solution, got tired…any help…

I have three movie clip

one is: car
second is: frontwheel
third is: backwheel

I added two buttons (play and stop)

right clicked on the button: actions :

on (release) {
car.frontwheel.play();
car.backwheel.play();
}

then went for stop button right clicked actions:

on (release) {
car.frontwheel.play();
car.backwheel.play();
}

it doesn’t work…

I have instances…for car and for wheels.

I don’t know how to attach the car instance to this example.

any help…thanks