Error when calling stop and play functions

The javascript API for jwplayer errors in these conditions.

If the video was already stopped and I call jwplayer('video').stop().

or

if the video was already running and I call jwplayer('video').play().

I want to stop the video whether it is buffering, playing or paused. What is the best way to do that. I tried calling getState() but that isn't accessible while the video is buffering.

Thanks.