Polish f16 spares shortage

Just been over at the f16.net web site and they had an article saying that the Poles are having problems with their brand new F16s.
They have 27 or so on the books with only approx 16 up and running, how can this be possible?
Im bit of a fan of the F16 but the poles cant be too happy with the current situation?
I know the Dutch are having problems also with the F16 so why are these operators having problems? could the heavy useage of the F16 by the USAF be a reason why spares are in short supply?