I'm using Win XP so threre is no Run As Admin problem. Tried to diable firewall and antivirus during installation but same result. There is no problem in the device manager with the Hamachi NIC. Still reporting problem with the driver.
However, there seemed to be a problem with Hamachi VPN network I used. When deleting that and creating a new network I now have green icons in the Hamachi client for all connected computers in the network (and chat is working), despite the reported driver problems. I guess the problem is the Diagnostic Tool not reporting the correct status. Now I only have to figure out what firewall settings to change to get everything going...