wxfalscolor not displaying

Hello there,

I'm testing DIVA with a real project that wee are designing.  I bult a simple box and exploited to create different Srf (north-south-west-etc) I try to run a visualisation image simulation but teh results comes out as a black image, So I guess if this is wrong all my simulations will be. Also I did a radiation map simulation over a grid and I get the following results (see image attached) Its strange that the roof gets no radiation at all.

I've also uploaded the rhino file V4 in case you'll like to give it a try.

Thanks for your help