VPN between 2 networks with same IP address scheme (Windows)

Problem is, the routing does not work. Solution is: On DOS command prompt, type

route add 192.168.1.84 MASK 255.255.255.255 192.168.1.160

...1.84 is the number of the computer you want to contact in the other network, ...1.160 is the client IP address of the VPN network connection.
To prevent your traffic into the Internet to go through the VPN, use:

route change 0.0.0.0 mask 0.0.0.0 192.168.1.250 metric 20

(.250 is the local network gateway into the internet)
If it gives the error: "The route addition failed: The parameter is incorrect." or "Hinzufügen der Route fehlgeschlagen: Falscher Parameter.", try using another local IP address. I found, the local IP address should not be too distant from the VPN client IP address.

Another annoying error I had, was that after some time of a working connection, I could not reconnect the VPN:
Error 619 came up, german: "Fehler 619 Ein unbekannter Fehler ist aufgetreten" nach "Benutzername und Passwort werden verifiziert".
My solution was, to set my LAN connection on a new IP address. Other people solved it by reinstalling their NIC card.