OpenVPN Access Server relies heavily on iptables rules. And adding PPTP network interfaces may interfere with AS operation. I desperately need help getting two services to run properly on the same Ubuntu 10.04 x64 server.
One solution would be to share the networks. E.g.: Your openvpn server does have the ip 10.0.0.1. The clients do have the ip range 10.0.0.20-40. Then you can put following values to your /etc/pptpd.conf: localip 10.0.0.110 remoteip 10.0.0.111-119
I am using this setup because I needed a pptpd instance for my ipad. I did not find a working solution for openvpn within iOS.