Brighten 3D portal

Hi Guys,
i buit a tank in blender. the 3D portal is very dark.
even though I have tried everything regarding lamps, it wont brighten the portal.
Is there a way I can make the world brighter?

The portals in the area lamp is to help brighten indoor scenes, by telling Blender where windows are and where light should go more. A screenshot of what you are doing would help.

When i booed up this AM, it seemed to have fixed itself.
thanks for the reply