Hi Anders,
About the USB service issue the “Package redistribuable Microsoft Visual C++ 2012” solved the issue. Now it works fine.
About the firmware installation issue, to use the command line firmware installation tool, you need to have the “Tracker URL” information, use “tet-tcp://<ip-adress>” or “tet-usb://<serial number>” depending of the Tobii REX firmware version. With that information, it works fine and the Tobii REX have a new Firmware.
Thanks. Francis.