OBD-II & Skoda Octavia TDi
VAG-COM is not OBD-II software! It emulates the dealers' proprietary tool, and uses protocols quite different from generic OBD-II. Since the Scantool.net interfaces have a OBD-II protocol-engine in them, they aren't compatible with VAG-COM.
VAG-COM does work fine on a TDI Octavia if you use a compatible interface.