Panther 10.3.2 server & VPN config

Another newbie post here, but after much effort I finally have DNS working internally as well as DHCP. Next is VPN and I'm at a stumbling block: I setup VPN for L2TP, not pptp with what seems like resonable information (group, IPsec shared secred, ip range), and enabled some inbound ports on my Netgear FR114P router that I found at another site (UDP on ports 500 & 4500; IP on 50). Whenever I try and start VPN, it starts Panther's firewall and only starts VPN for a slit second. I tried enabling L2TP on Panther's firewall thinking that it too needs to run and it listed a completely different port (something like 1701?). Firewall starts okay but VPN again just flashes on momentarily. 1) Thoughts? 2) Any step-by-step out there that I can use or leverage? Best, Charlie-