Hello Sandy,
Thank you for your professional answer. I really appreciate it.
I owe you and Xerox an apology. This is not really easy to write that, because I need to admit publicly that I am an idiot.
Here what happened yesterday. I bough another device (a scanner) and tried to install it. Surprisingly, I had exactly the same problem as I had with the Xerox printer. I looked deeply into the issue, but was not able to locate the problem during several hours. Finally - accidentally - I switched USB cables and suddenly all started to work! I checked the cable (also used during Xerox installation). It was broken! It let the devices to "see" each other, but did not let them to communicate.
I owed you that confession.
Kindest regards,
Andrew