What's the max number of incoming connections (aka VPN) Windows 7 supp

What's the max number of incoming connections (aka VPN) Windows 7 Ultimate supports? I'm getting an error every time I try to connect one machine while the other is connected. Error 937 I believe. Does this mean that windows 7 Ultimate only supports one vpn connection at a time without upgrading to the server OS ?

It works when I disconnect one machine, allowing the other to connect.

???

This question has come up before. You are only allowed one connection to a Windows 7 machine unless running a Windows server but there are a couple more options.

http://www.sevenforums.com/network-sharing/57032-multiple-vpn-connections-same-computer.html

Thanks. Good. Windows 7 only accepts 1 incoming connection at a time. So everything is working as it should .