Problem with nested movie clip animation

I'm converting a program from AS3 to JavaScript and I'm running into a problem. I have a movieclip with 3 different frames, each playing a different animation. I want to switch from one animation state to another like it does in AS3. When I first play the clip, I use:

myMC.on('tick',function(){ this.gotoAndStop(0);} );

and it plays the animation in the first frame perfectly. However, when I use the same code to switch to another frame, such as:

myMC.on('tick',function(){ this.gotoAndStop(1);} );

The animation clip doesn't play - the movie clip stays on the first frame. It's as if the act of switching to one of the other nested movieclips breaks the animation playback. Any ideas?