OS: VSTA home editition (norwegian, so please be aware of translation mistakes)
Location: France, collective with 5 persons all using internet
internet supplier: Neuf (neuf box)
VPN version: 4.8.01.0590 (for vista). tunnelling to host in Norway
Firewall: NO, only the integrated firewall in vista

PROBLEM: VPN connects, internet disconnects
SOLUTION: internet-connections --> advanced settings --> changed preferred order of connection used by internet services. I put the VPN connection on the very bottom.

VPN transport settings: "allow local LAN"  (YES), "transparent tunnelling" (NO)

btw:
CANT CHANGE USE REMOTE GATEWAY as in XP (in my VISTA version at least).

8/2-08 solution nr 1 that worked, but not for long (!??)
I went to the TCP v/4 in my VPN connection. Then added a standard gateway on the "advanced" option. It worked the first time.

10/2 -08 the solution nr 2 that worked but only for one day (??!?)
Tried all "transport" settings in vpn, and strangely one of the transparent tunnelling options worked  ONE time...strange.

13/2 -08 The SOLUTION that still works!
After som days of vpn break i decided to take a fresh look at the problem again. I mailed som tech-dudes that recommended everthing that i have tried so far (firewall, all transport settings, suicide etc). SO, no help.
But as an amature i try everything. I went to "networkconnections" on my vista and then to "advanced settings" were i changed the preferred order of which connections will be used by network services. I put my VPN connection at the very bottom.

I connected VPN, internet shut down for some seconds, but then came back, BOTH VPN and NETWORK is STABLE!

So It worked, hurra! But this is so strange, because my VPN connction now is connected "local" and "internet", but my internet connection says only to be connected "local" (???!!). But it still works.....though strangely........im just happy it works, dont care how:D

BTW: I think my problem is related to my network-supplier or/and to the fact that we are five people using the internet. But i am the only one using VPN, so that should not really be a problem. Network supplier issue or VISTA is my best guess because thats the two things that i have changed since VPN and internet worked together.