I have the same issue but only with certain ISP/routers. I have a wireless network at work and everything was working correctly but when I got home I was getting the VPN private IP instead of the local IP. I have access to another wireless network at home and connected to that and it works!
I'm guessing this is a router issue? Kind of disappointing as I'm trying to use hamachi to alleviate issues I'm having with my work router's built in VPN not working with some client's routers. I guess I'm glad I discovered this issue before paying anything.