Why is My Lighting Creating a Triangle on the Ground? More trouble going through the Roland Hess Blender Foundations book.  When I create the indoor scene in Blender, I get an odd light triangle on the ground.  I don't know why this is happening.  Help is appreciated!!

The blend: https://www.dropbox.com/s/zg96duw8av52st3/Flower%20019.blend

The last render: https://www.dropbox.com/s/9u9mldvxhxh79fc/Blend%2019.png?dl=0
It's your sun lamp near and far Clipping values.

Adjust the Clip Start and Clip End values for the Spot.008 lamp that is acting as sun.