Hi, could you try the following, whilst the device is connected.
1) Go into device manager (right click on my computer and select properties, then select the hardware tab and click on Device Manager)
2) Look under USB device, if there is an exclamation mark saying unknown device then right click on that and select uninstall.
3) Disconnect the humidiprobe for a few seconds and then plug it back in, now continue with the installation process by selecting (Yes, this time only and Install software automatically-then when prompted select CONTINUE ANYWAY).
Let me know how you are getting on.