The GVC client may fail to install if a previous installation of Safenet or GVC was not removed completely. The Deterministic NDIS Enhancer (DNE) driver may still be bound to a network adapter. This is typically observed with an error message similar to "It appears that you've uninstalled the SonicWall Global VPN Client. You need to reboot your computer before setup can proceed."
A Cleaner Tool can be run which will remove the DNE.