I used prf's from the XP 4.03 version (new vista install) and recieve the follwoing error on the Vista box when trying to connect:
Cisco Systems VPN Client Version 5.0.00.0340
Copyright (C) 1998-2006 Cisco Systems, Inc. All Rights Reserved.
Client Type(s): Windows, WinNT
Running on: 6.0.6000
17 15:53:10.938 05/11/07 Sev=Warning/2 CVPND/0xA3400015
Error with call to IpHlpApi.DLL: GetBestInterface failed, error 1231
18 15:53:10.938 05/11/07 Sev=Warning/2 IKE/0xE300009A
Failed to set up connection data
19 15:53:10.938 05/11/07 Sev=Warning/2 CVPND/0xA3400015
Error with call to IpHlpApi.DLL: GetBestInterface failed, error 1231
20 15:53:10.938 05/11/07 Sev=Warning/2 IKE/0xE300009A
Failed to set up connection data
PLEAS HELP