Transparent lens flare issue Motion 5.4.2

Hello, I'm trying to create 2 lens flares moving around an image on a motion path, I successfully created the motion path with the 2 lens flares, however I can't get the lens flares to be transparent, there are two giant black bars that extend around the lens flares. I changed the blend mode to "Add" but still no luck. I'm wanting to export then open and use in a project in FCPX so I can put it over other footage.. Screen shot is attached.

Thanks for your help!