Cubase 6.5 automation problem

I have Cubase 6.5 ( 64 bit) on my PC (Windows 7,64 bit) and everything seems to work except the automation on the vtst instruments and audio effect on the inserts.So whatever i try to write on the buttons of the vst instruments,Cubase doesnt read it.Strange thing is that when i put on “Show automation” the automation is shown on the lanes ( for instance Cut off etc) but you cant hear the changes and you dont see the parameters change in real time…Anyone??