This already happened to a computer I had to fix.
The solution is quite simple. Keep the list handy, because this problem usually appears when the connection is not cleanly closed (unplugging network while connected, computer suspend, etc)
This is how to solve:
1 – Start Menu
2 – Network
3 – Click on Network Sharing
4 – Click on Manage Networks and in the new window opened
5 – Right Click on Cisco Adapter and click on Diaognise.
6 – Reset the Network adapter
7 – There will be a message stating that there is limited connectivity and you shouldn’t bother with.
8 – Restart the machine.
9 – After restart, try to connecti to VPN.
If you can, update your Cisco VPN client. Newer versions don’t have that bug.