May 13, 2009 - 6:20 PM (GMT)
For all you out there who are running a Macbook Pro, using a Cisco VPN client and running into "Error 51: Unable to communicate with the VPN subsystem".
Here is what you have to do to fix it. Go to Applications > Utilities then open Terminal. Once you get to the prompt, type in:
sudo /System/Library/StartupItems/CiscoVPN/CiscoVPN restart
You will be prompted to enter the password for your computer. This procedure will restart the things that need to be restarted. You should then be able to use your VPN client again.
For newer mac's you can try this if the above does not work...
sudo kextload /System/Library/Extensions/CiscoVPN.kext
1/24/2012 4:36 PM UTC