My internet provider works through VPN connections, and I always have the problem with it.
I install network-manager-pptp and pptp-linux (and at the and all that relates to the network manager), go to vpn connections and can't add anything in KDE 3.5 or KDE 4 (it writes that there is not interface for a vpn service).

Therefore I have only one way to add this connection, I install gnome, add this connection there, and it appears in KDE, it's not comfortable way isn't it? ;)

May be it's only kubuntu trouble? I don't know, please tell me what happens in other distributions if you have this experience.