1) Install the more recent PVS-version that is available on Aminet. It works then. Be careful about the Mhz - default is set to 110Mhz and you can't set it higher in the GUI. I never need/use PVS and prefer to set my ENV-Vars directly.
Don't know about ShowAmiga96, but I don't think that both PVS and SA96 have similar problems.