I had the same problem with a Windows 7 Home Premium machine. It seems that in Windows 7, you need to have the firewall enabled. In Win XP, it works better if the firewall is disabled. Also, some AV can get in the way. We have had good luck with MS S...
I have 2 computers on the same network. I can connect with one computer and not the other. Both are using the same VPN Account. Both are running Windows 7 Home and the firewall is completely disabled. Both are running Microsoft Security Essentials....