Does this indicates that the client application is not compatible with Windows 8, at least for now? There is a workaround though. Following are the steps to make it to work.
- Open Registry Editor (like type regedit.exe).
- Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\vpnva
- Locate key DisplayName, like mine shows @oem3.inf,%vpnva_Desc%;Cisco AnyConnect VPN Virtual Miniport Adapter for Windows
- Change it to Cisco AnyConnect VPN Virtual Miniport Adapter for Windows
- Close then open Cisco AnyConnect VPN Client. Retry to connect. It should work from here on.