I can't play past the end of the green bar

It looks to me like you got about a 17-second preview of an HD comp that is a single layer with no effects applied, no animation, and no reason that I can see to have that whole clip as a comp. A 17-second ram preview of an HD comp at full resolution on a pretty good system is pretty good. After Effects is not a Video Editing app. It is a motion graphics, and compositing app designed specifically to create shots and effects that you cannot create in a nonlinear editor like Premiere Pro. 

You can preview at a lower resolution, skip frames, or use low-resolution proxy footage to get longer ram previews, but you can't force AE to be a video editing app. More than 90% of my comps are under seven seconds long and are just shot or effect. I only use After Effects to work on the frames that need visual effects added or graphics added that I can't do in an NLE.

If you are new to AE please start with the User Guide and go through some of the beginner tutorials so you can figure out how the UI works and what to expect. If you want to do something with that shot you have in your comp please give us a detailed description of exactly what you are trying to achieve. When I saw the first frame I thought you were creating the graphics for the open that only run about 4 seconds. That would be a good job for After Effects, but the most efficient workflow would be to render that opening sequence to a visually lossless production format, import it into Premiere Pro and cut it into the film.

This is no error - but a miss of knowledge how AE actual works. Spend some time with the beginners tutorials.

*Martin