Spotlight shines out of range

Hi, I’ve created a spotlight inside a cube house. As you can see on the image, it’s directed to the front wall of the house, still there is a huge glow on the right out of the house, even while the range is smaller than the distance to the outer wall, how is this possible?

http://img404.imageshack.us/img404/904/problemlight.jpg

I don’t know, how can I check this?