Do you have dynamic vpn configured completely like the dynamic vpn getting started document? Do you have any users with the interface that you are trying to connect to specified as the external-interface?
(security ike gateway <name> external-interface <interface>)
Do the following to see what interfaces dynamic vpn is available on:
start shell
cat /var/jail/etc/httpd.conf
Look for a line that says IKEGatewayInterfaces <interfaces>
If the interface that you are trying to connect to is not there, dynamic vpn should not be available on that interface in 10.2 and later releases.