Paul, I am using the OpenVPN GUI v1.0.3 from the link below and I have also included a copy of my client side configuration file on the Vista laptop.
##c:/program files/openvpn/config/vpn.domain.com.ovpn float client dev tun dev-node openvpn proto tcp-client remote xx.xx.xx.xx 1194 route-method exe persist-tun persist-key ca ca.crt cert client1.crt key client1.key ns-cert-type server tls-client comp-lzo ping 10 pull verb 4 http://www.openvpn.se/files/install_packages/openvpn-2.0.9-gui-1.0.3-install.exe
