One user had troubles with the Cisco VPN Client 4.9 on a brand new MacBook Pro. Whenever you tried to connect, it just failed and without any warning. I turned on the log and found the following entry:
Unable to bind to IKE port. This could be because there is another VPN client installed or running. Please disable or uninstall all VPN Clients other than the Cisco VPN Client.
I then found out this thread which solves this problem. Here are the steps.
1. Close VPN Client.
2. Open Terminal and change directory to /etc/CiscoSystemsVPNClient/Profiles .
3. Use a text editor to open the profile.
4. Add the following line to the profile.