There are 3 changes here:
- Enable sky/environment in the foregroundlayer:
In Blender Internal it wouldn't matter because the sky wouldn't be rendered anyway because of the premultiplied alpha. In cycles that makes sure objects can be illuminated by world color or texture
- Set AO to 0.05 if using Cycles.
Ambient Occlusion in Blender Internal will only make things darker, hence strength can be 1. An AO value of 1 in Cycles however would light up the scene way too much. A value of 0.05 adds a resonable hint of light which can help to eliminate noise. If the user doesn't want that he'd have to disable AO anyway.
- Change the size of the cube in foreground layer to dimensions of (1,1,1), which is a better starting value for most test scenes, and also move the mesh up 1 Blender Unit so that the cube sits on the ground. That makes reviewing the tracking scene easier. Besides, the lower part of the default cube would be cut off by the background plane anyway.