This is a repost of a post from an old blog, made on January 3, 2012, that used to be on:
http://adminramble.com/cisco-vpn-client-error-56-service-starts-and-then-stops/
Original post:
I was installing Cisco VPN client on a laptop today and after the installation whenever I tried to run it I got
Error 56: The Cisco Systems, Inc. VPN Service has not been started. Please start this service and try again.
So naturally I went to Administrative tools > Services and tried to start Cisco VPN service, but whenever i tried I got:
service on local computer started and stopped.some services stop automatically if not in use by other services or programs.
I tried reinstalling Cisco VPN client but I still got the same error. The solution that worked for me was to turn off Internet Connection Sharing (ICS)
Go to Administrative Tools > Services > right click Internet Connection Sharing and go to Properties > On General tab stop the service and change startup type from Automatic to Manual