Getting Loopy

Seems almost silly to ask but I have a simple animation with a loop. 

1. Frame 1  (0) code:
2. var _this = this;
3. _this.stop();
4. var _this = this;
5. _this.IndexNext1.on('click', function(){
6. _this.gotoAndPlay('Indx1');
7. });

This works. 

On frame 100, if I use this code, it doesn't work:

1. var _this = this;
2. _this.gotoAndPlay('indx1');

However, if I send it to a different frame with this code, it works:

1. var _this = this;
2. _this.gotoAndPlay('repeat1');

I figure I'm missing a basic concept here, but I don't know what it is.  Is there a better way to move the playhead to a labeled frame?

Thanks!