VoxATC X - Unable to declare emergency

Hi,I am testing VoxATC X and feel great improvement against older versions, but:1. I am unable to declare emergency. When I fly IFR LKPR-LKTB (Czech republic), after departure from LKPR, "declare emergency" appears in prompt window menu (I realize it is awailable at the time). But if I declare emergency, controller still replies "unable at this time". I have tried it along the several phases of flight (departure - climb, enroute at FL...), but still the same reply "unable at this time". What is the reason ?2. I have to wait about 1-2 minutes after frequency change very often, before green text in prompt window appear. So I can not contact controller. My FPS is about 12 at this time. May be slow CPU the problem ? Thanks for repliesJiri