daylightfactor results seem wrong

hey guys!

im trying to run a daylightfactor simulation, like i did before already. later i want to use galapagos to optimate.

but before i get to this point i´m getting in trouble. i want to simulate a ceilling with a different nummer of skylights, which are created with grasshopper. but the results grid seems very wronk to me, like green = zero % daylightfactor. i´ve a screenshot uploaded. i have no idea what the problem is. 

i´m looking forward to your answers.

thank you

melanie