Interior Scene w/ MR Sun and Sky problem

I am creating a interior scene using max 2009 w/mr sun and sky.

I get the error message "no photons stored after emitting 10000 pnotons from mr/sun01.

I know this is usually because the photons don't have anything to bounce off of so I created a sphere to enclose my scene and flipped the normals so they are facing inward.

I also applied a standard white material to the inside of the sphere.

Lastly, I put a check in the mr Sun Photons box "use photon target" and set the scene to 600 feet.

I have created new sun and sky systems, rebooted my computer and elliminated all other light sources trying to solve this.

Yesterday it was working greate. What could I have changed that would cause this?