kerio and vpn client

If you're talking about Kerio V. 4.1, I had the same problem. I'd suggest making a rule to allow cvpnd.exe UDP inbound on local ports

62515/17/19/21/23/24 and outbound UDP on port 500. If that doesn't work, disable Kerio when you initiate your VPN connection. You can try using Cisco's Stateful Packet Inspection in that case, but keep in mind, that may cause conflicts with the Kerio Firewall engine. If you still run into problems, post back and I'll give you a couple of other things to try.

As a followup, I just tried 4.1 beta 5 release, which incorporates some predetermined rules with VPN. I got my Cisco VPN to work with it in about 2 minutes.