I found an interesting post by Joe Harris (author or Cisco Network Security, Little Black Book), and unfortunately Cisco isn't going to help us out, but he does make a recommendation, check out his blog:
6200networks.com
September 12th, 2008 • Related • Filed Under
Filed Under: Security
You may have noticed that the Cisco IPSec VPN Client does not currently support
64-bit Operating Systems nor will it. If you have a
need for an IPSec Client that does have 64-bit OS support, NCP Secure Communications has a Universal VPN
Client that is 64 Bit compatible and will even import/convert your existing
.pcf profiles for a seemless migration to a 64-bit client. More information
regarding their products can be found by visiting their products page as well
as specific configuration information related to configuring their client with
Cisco products is found here: NCP to Cisco Config Guide
NCP engineering is recommended and this looks like the most
recent data sheet (second page is the detail):
Data Sheet. Hope this helps