Hi Artur,
Thanks very much for responding.
These are very strange drivers because the "USB Serial Port" under COM & LPT only appears in Device Manager when the USB cable is connected to the PC and the ProfiLux. When the cable is disconnected the port disappears. So in order to unistall the driver, the two must be connected.

In any case, I did as you instructed. After installing the package you linked to and connecting the ProfiLux, COM5 appeared in the COM & LPT section.

I then set the COM number in the Interface field to 5 and got an Error 28.
I then set it back to "1" and still got Error 28.
I then tried the "Scan COM..." button and got a series of Error 28 + "No device has been found at all COM ports!" message.

I thought this must be a problem with this computer so I followed the instruction on a second Win8x64 PC with the exact same results.

In the "System"->"Communication" menu on the ProfiLux there are three items, COM1, COM2 and LAN. Are there any specific settings for these items?

Cheers,