Unable to establish VPN connection with SBS 2K3 server

I’m trying to establish branch office connection to my SBS server via VPN. I’ve set up the server firewall to allow VPN passthrough. When I try to connect I get the error message, “xx.xx.xx.xxx is not set up to establish a connection on port ‘pptp’ with this computer.” I get the same message when I try with the firewall down. I have a static IP address for the server and address requests to that IP address. Does anyone have any ideas? Thanks for reading this.