I don't think you understood me. When you get the color bars there is missing footage in your comp. Try scrubbing through your timeline to the place where the color bars appear in your render. You should see the same thing in the comp window. Find the layer that is giving you the color bar image, right click and select find in Project, then right click the footage and use the replace footage option to find the footage.
If that does not fix your problem please give us a screenshot with the CTI at the point in your render where the color bars appear and reveal all properties of the problematic layer.
I just looked up the codec you are using. It's a highly compressed 3rd party codec and that alone could be causing your problem. There are lots of users of that codec that have problems. If you do not have missing footage in your project then Transcode the original screen capture footage to a suitable production quality codec and replace the footage in your AE project with a standard digital intermediate codec. Jpeg compressed Quicktime is probably one of the most versatile and dependable DI codec.