I installed Gutsy this morning and followed my own instructions above for getting Relakks VPN/PPTP up and running. My efforts failed.
After some Googling around, I discovered there is a bug
in knetworkmanger and an issue with how it refers (or in this case does not refer to) ppp & pptp
There is a work around using Gnome's Network Manager
I had to do the following:
Install Network Manager Applet through the Add/Remove in the Ubuntu menu.
Install the plug-in for your connection type - either network-manager-pptp, network-manager-vpnc (Cisco) or network-manager-openvpn (use Synaptic Package Manager or apt-get).
Left click the network manager applet (two monitor screens one behind the other probably in the bottom right of your screen) and select VPN Connections->Configure VPN->Add, then enter your connection details. There may be another icon that looks similar to this, which will bring up a dialog 'Connection Properties' if you left click it - this is not the one you want. Reboot if the applet is not visible.
Left click the network manager applet and select VPN Connections then click on your connection to connect.
If your new connection is greyed out and unselectable, or all you see is Manual Configuration...:
Backup /etc/network/interfaces to /etc/network/interfaces.original.
Delete all lines from /etc/network/interfaces not including the string "lo" (leaving two lines, probably the first two, beginning auto and iface).
If the above step leaves you with no internet connection at all, replace the original file and reboot.
I had to reboot a couple of times as well as add my Relakks information and then go back in and reedit.
It took a little patience, but I am posting this from my VPN connection.
I hope this information helps others!