Is there a particular reason why you are wanting to use an old 4.x client (4.8 released January 2007) with an ASA latest release?
I have used the current 5.0.07.0440 client successfully on 64-bit Windows 7 with ASA 8.4.
Just to test I downloaded 4.8 client and note this warning page is presented:
Dear Valued Customers and Partners,
In an effort to assist our customers and partners in using Cisco's recommended VPN software releases, Cisco is archiving and deferring (i.e. removing) from Cisco's Software Center potentially vulnerable and older software releases of the Cisco Secure Desktop (CSD) and of the Cisco VPN clients (Cisco VPN client (IPsec), SSL VPN Client (SVC) and Cisco AnyConnect VPN client).
Cisco strongly recommends use of the latest VPN client and Cisco Secure Desktop software versions, as available on Cisco's Software Center, in the
Latest Releases folder for each product. Recommended software includes fixes to security vulnerabilities announced by PSIRT, incorporates the latest feature-sets, and supports best practices deployments.
As new updates are released, the most current VPN software versions will be published on Cisco's Software Center. Prior releases will be superseded and either archived or deferred from the Software Center. As an accommodation to our customers, archived releases will still be available on Cisco's Software Center in a separate All Releases folder. Deferred releases will be removed from Cisco's Software Center and can be obtained by special request through Cisco's Technical Assistance Center (TAC).
All archived and deferred software available through the Cisco Software Center or through TAC is provided by Cisco expressly on an "AS IS" basis, without warranty of any kind. Such archived or deferred software may contain known security vulnerabilities or other bugs that have been fixed in subsequent software versions.
Before using any archived or deferred software version, please consult the Security Advisory Information page.
Compatibility information documentation for Cisco ASA, ASDM, CSD and VPN clients is posted here:
Cisco ASA 5500 Series VPN Compatibility Reference
- The Cisco ASA VPN edition team
Unfortunately it won't install on 64-bit Windows 7 so I can't test it independently on an ASA with 8.4(1).
Note that, notwithstanding the Cisco VPN Client 4.8 Release Notes, the Compatibility Reference mentioned above states:
Cisco IPsec Clients
All releases of the Cisco ASA 5500 series support the following Cisco IPsec VPN Client releases:
•Cisco VPN Client Release 5.0.0.7 supports Microsoft Windows 7 x86 (32-bit) and x64 (64-bit), Windows Vista x86 and x64, and Windows XP x86
•Cisco VPN Client Release 5.0.0.6 supports Microsoft Windows 7 x86, Vista x86, and XP x86
•Cisco VPN Client Release 4.9.01.280 supports Mac OS X 10.5 & 10.6
•Cisco VPN Client Release 4.9.01 supports Mac OS X 10.4 & 10.5
•Cisco VPN Client Release 4.8.02 supports Linux (Red Hat)
•Cisco VPN Client Release 4.6.02 supports Solaris UltraSparc (32 and 64-bit)
Refer to the Cisco VPN Client Release Notes for more details on capabilities and limitations.
Cisco VPN 3000 Series Concentrator, Version 3.0 and later. Using IPsec over TCP requires VPN 3000 Series Concentrator version 3.6.7.a and later.