Simple telltarget/mc question

Hi,

I have a simple problem,

I have a button at the root of a MC that when clicked plays another MC.

But when I use the following code:

on (release) {
tellTarget ("_root.mc-room") {
gotoAndPlay(2);
}
}
it works but i know this is deprecated, however when i try:

on(release) {
_root.mc-room.gotoAndPlay(2);
}

nothing happens?

Any suggestions.