SSH 4.3 VPN with Ubuntu Edgy - Can't get it to work

I have followed every single guide I can find on the net (and they are
subtly different) but I still can't get SSH 4.3 VPN to work. I have
two systems, both upgraded Ubuntu Edgy boxes. I followed the guide at:

And I can't ping between two computers. I tcpdump the tun0 interface
on both and all I see is outgoing packets.

I did somehow sort of manage to get it working between myself and my
Debian Etch box (2.4 Kernel) in that I could sometimes see packets go
both ways on the etch tun0 interface but the ubuntu boxes were still
not ever seeing anything return.

I literally did exactly what the guide above says (as well as trying a
few others).

I've checked routes and the packets are definately going out the tun0
as expected. iptables is not running on either host.

ip_forwarding is enabled on both hosts.

PermitTunnel yes
AllowRootLogin yes

on the server.