I had a similar problem using a Cisco IPSEC client and NAT. The problem had to be resolved at the VPN server side by specifying a specific port to use.
I read IPSEC uses random ports to set up and receive the session (sounds similar to FTP), so when my laptop made an outgoing request on one port, the response came back on another port and the NAT box dropped it. Once my IT group specified a single port to use, the problem was resolved. Another way to resolve it would be to have all external traffic forwarded to your laptop, but I don't know how to do that on e-smith.
Hope this helps,
Greg