B253 beta problem

Hi all,

I have a simple scene using Blender 2.53 beta.
I modelled a carton box with cover and added to lamps (spots) to the scene.
Lamp settings are default. If I hit Image to render an image it comes up with ugly, coarsed shadow (see attachment).
I’m working on Mac OSX 10.6.4, Intel I7, 64 Bit.
What am I missing?

Thanks for any help!