spot light casting own shadow?

Hi,
I'm attempting to light a building from below using some spot lights, but they seem to be casting their own shadow, or rather, a shadow on the ground plane.
My environment lighting setup is just an environment dome light; nothing too fancy.
Is there any way to exlude lights from casting shadows in Clarisse 4.0? I'm using SP6b.
I'm uploading an image showing what I'm seeing.
I'm attempting to light a building from below using some spot lights, but they seem to be casting their own shadow, or rather, a shadow on the ground plane.
My environment lighting setup is just an environment dome light; nothing too fancy.
Is there any way to exlude lights from casting shadows in Clarisse 4.0? I'm using SP6b.
I'm uploading an image showing what I'm seeing.