_currentframe help

i have a button inside a movieclip, when i click the button i want it find what the current frame is on the main timeline and then perform an action depending on what the current frame is. so for ive used the code below and ive modified it a bit but i still cant get it working. can anyone help me.

on (release) {
if (_root._currentframe == “BOMB”) {
trace (“true”);
} else {
trace (“false”);
}
}

Thnx,
Brendan Smith