Multiple users logged on

In a multiple user environment (win 10), the second user that logs on gets an error indicating "Error initializing tcp/ip.". Besides logging of the first user before logging on the second user, is there a way to solve this problem?

Yup, there is.

Only one process can open a port for listening, so either disable networking if you're not using it, or if you are then assign a different port to each user.

If you're using W10, it's likely only a few people, so just increment the port number in options for the non-primary users.  Then to send to those users, add that port number onto the IP address of the machine.  If 56784 is your port number, then set it like this:

192.168.1.5:56784

Tom