Projector taking aspect ratio of clip

[justingeller]

I want to make a template of the exact layout of my lights and put it in a 16:9 frame and know that the projector is going to match up exactly. I created a macro with a video clip and the connected it to the projector in the IO tab. In the Editor mode, I'd like to make the projector the same aspect ratio the video clip. So I go back to the Editor tab, select the projector, and try "Width from Aspect" or "Height from Aspect" and says "Please Assign and IO Texture to your projector first" Is this an error or am I going about this the wrong way? Thanks!