hmmm. on a 338 or a 538 I would begin by opening TCP & UDP 500 and then create the VPN Tunnells. But a 318 is using different software, so I cannot say for sure. I would delete the IKE & VPN Policies, creat the rule, then recreate the VPN & IKE Policies.
Also you may want to diable the default 'Block Always' rule and see if the VPN works. That will at least isolate if its a firewall or other issue.
I would advise you to continue with the Shrew VPN Client, it is way better and at the very least it's just as secure.
Uou can email me the config and I will roll it out in the lab and get it operational, then send it back to you. Just make sure you NEVER send anyone you passwords or static ip's as they can be used to break into your network.
...I feel a bit obligated to say this as well. Netgear makes some great products, but I wouldnt use the 318 for anything more than a few PC's on a small network and I would never use it as the VPN endpoint. It's kinda slow, not very many patches and the backplane is tine. An FVS338 is faily inexpensive and does a great job. Not that Im saying throw the 318 away, just next time go for the 338 or 538 if you want dual wan ports with roll-ver or protocol binding. If you want any advice on future purchases, let me know and I will outline what I use regulary for my customers.
http://www.netgear.com/Products/VPNandSSL/WiredVPNFirewallRouters/FVS338.aspx
http://www.amazon.com/Netgear-FVS338-ProSafe-VPN-Firewall/dp/B0006OCZGW