The Shrew VPN client appears to be a good alternative to the Cisco VPN Client on x64 Windows 7. However, since installing it I've seen fairly regular BSODs. Minidump attached:

Microsoft (R) Windows Debugger Version 6.11.0001.404 AMD64
Copyright (c) Microsoft Corporation. All rights reserved.


Loading Dump File [D:\Temp\020810-23431-01.dmp]
Mini Kernel Dump File: Only registers and stack trace are available

Symbol search path is: SRV*d:\symbols*http://msdl.microsoft.com/download/symbols
Executable search path is: 
Windows 7 Kernel Version 7600 MP (8 procs) Free x64
Product: WinNt, suite: TerminalServer SingleUserTS
Built by: 7600.16385.amd64fre.win7_rtm.090713-1255
Machine Name:
Kernel base = 0xfffff800`0285f000 PsLoadedModuleList = 0xfffff800`02a9ce50
Debug session time: Mon Feb  8 18:08:12.887 2010 (GMT+1)
System Uptime: 0 days 7:52:06.120
Loading Kernel Symbols
...............................................................
................................................................
..............
Loading User Symbols
Loading unloaded module list
....
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*                                                                             *
*                        Bugcheck Analysis                                    *
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Use !analyze -v to get detailed debugging information.

BugCheck A, {0, 2, 0, fffff800028d50b6}

Unable to load image \SystemRoot\system32\DRIVERS\vfilter.sys, Win32 error 0n2
*** WARNING: Unable to verify timestamp for vfilter.sys
*** ERROR: Module load completed but symbols could not be loaded for vfilter.sys
Probably caused by : vfilter.sys ( vfilter+29a6 )

Followup: MachineOwner

Machine is a brand spanking new Dell Precision T5500.

Superuser appears to have several recommendations for the Shrew VPN Client as an alternative to the Cisco VPN client on 64 bit machines, so I wondered if anyone here has seen this problem and possibly found a solution to the problem?

I've decided to run the VPN client under Windows 7 compatibility mode for the moment (Vista SP2) with administrator privileges to see if it makes a difference. Oddly, the VPN doesn't necessarily need to be connected. I've noticed it when browsing using Google Chrome and Internet Explorer, usually when I open up a new tab.

If it carries on I think I'll be forced to shell out the 120 EUR for the NCP Client instead.