For windows 8.1 do that, if you get this error:

Secure VPN Connection terminated locally by the Client.
Reason 442: Failed to enable Virtual Adapter.

Solution: If you receive this error on Windows 8 or Windows 8.1 while trying to connect with the Cisco VPN Client then the solution is a simple registry fix.

 

  1. Click Start and type regedit in the Search field and hit enter.
  2. Navigate to HKLM\SYSTEM\CurrentControlSet\Services\CVirtA
  3. Find the String Value called DisplayName
  4. Right click and select Modify from the context menu.
  5. In Value data, remove @oemX.inf,%CVirtA_Desc%;. The Value data should only contain Cisco Systems VPN Adapter for 64-bit Windows.
  6. Click Ok.
  7. Close Registry Editor.
  8. Retry your Cisco VPN Client connection.

Instructions taken from here.
http://supertekboy.wordpress.com/2013/10/19/cisco-vpn-on-windows-8-1-reason-442-failed-to-enable-virtual-adapter/