juniper vpn not able to set rule for forwarding

edit

First, I was having diffculty in installing juniper vpn. I got pass that hurdle however when running the vpn has following error:

./ncui -h  host -f user.crt  -u sandeep -r RemoteAccessUsers -L 3  -U "login-host"

gives following error:

ip6tables: Bad rule (does a matching rule exist in that chain?).
ip6tables: Bad rule (does a matching rule exist in that chain?).
ip6tables: Bad rule (does a matching rule exist in that chain?).

I tried disabling the firewall as recommended here ( http://sanenthusiast.com/tag/failed-i... ) but this doesn't solve the problem.