Return to main timeline not working

I have followed a zillion threads about returning to the main timeline from an swf but can’t figure out what I am doing wrong.

I have an external swf loaded into an mc on the maintimeline.

When the sound is finished playing at the end of the external swf I want to return to the main timeline.

My code in the external swf is this:

stop();
mySound.onSoundComplete = function() {
_root.gotoAndPlay (“movie”, “explore”);
}

(where “movie” is the scene and “explore” is the frame label).

Nothing is happening.

The odd thing is that if I write…

stop();
mySound.onSoundComplete = function() {
_root.gotoAndPlay (1);
}

…it works (it goes to the main timeline, but not to the place I want).

I am going completely mad and really have searched every thread to see what I’m doing wrong. Please help!!!