Indirect lighting not showing well

Hi,
I am using GI trying to light up a room with sunlight (directional light as the sun), but it seems like something with the indirect lighting isn't working well or I'm missing something with the definitions.

Example 1- I can only see the spot of direct light coming through the window and the rest of the room is almost completely dark.
Example 2- I tried again with a simple scene, just a box with an opening in its roof, and again strange results:
The ceiling comes out completely dark and the shade falling on the red box is darker on the top than on the side of it...

You can see both of the scenes in the screenshots below.

I have made sure all my objects are 'Lightmap static'.
I made sure 'Precomputed realtime GI' is on and 'Baked GI' is off.
The Auto lighting calculation is on and I waited until it finishes calculating.

Does anyone have a clue what I may be missing here?

Thanks in advance.

P.S- Don't know if it's related, but in the General GI section of the 'Lighting' tab I get a notification:
"Directional lightmaps cannot be decoded on SM2.0 hardware nor when using GLES2.0. They will fallback to Non-Directional lightmaps".
Could it be something with my graphics card..?