White box in space scene

Hi all

I modified the starter.fps into a space scene doing the following:1) changed the skybox to a starbox set of created pics 2)removed the terrain 3) added a physical zone with a gravity mod of 0.

Everything is fine until I drop down a bit below my models and end up inside a white box with no top. Any idea why this might happen? I thought it might be the mission area settings but I played with those and it didn't make any changes.

Thanks

J