Cisco VPN Error #201 -
"The necessary VPN sub-system is not available. You can not connect to the remote VPN serve."
Explanation: Pretty Vague error message.. Usually this error means something happend to the VPN client you are using and one of more pieces (service or daemon) of your VPN client have failed or didn't start/run..
Suggestion, close and restart the VPN client. If the problem persists restart the PC, and look for other conflicting applications (another VPN client open) or check to see if your security/anitvirus software is blocking some of the services/daemons from running.
Worst case, uninstall the Cisco VPN client, reboot and reinstall the Cisco VPN client.