This is probably due to an old version of CBus Toolkit being installed on your computer.
CBus Toolkit older than 1.15 will not have the newer USB drivers required for the NAC/SHAC.
Your 5500PACA (PAC) or your 5500PCU (USB PC Interface) with their USB
connections will still be working, as they both use different "older" USB drivers.
Download the current Version Here: https://www.clipsal.com/learn-and-discover/trade-talk/trade-software-tools/c-bus-software