Hi,
I get the following information from Cisco website:
"The Cisco VPN Client supports:
•XP, Vista (x86/32-bit only), and Windows 7 (x86/32-bit only); Windows x64 (64-bit) support requires Cisco AnyConnect VPN Client"
http://www.cisco.com/en/US/products/sw/secursw/ps2308/
Please try the Cisco AnyConnect VPN Client from the above site.
You can also contact Cisco support for directly information.
Vivian Xing - MSFT