vpnc: port 500: Address already in use?

I've installed vpnc, kvpnc gui and the kernel support for tun. So I have a device /dev/net/tun , vpnc starts with no problems and no errors, but when I try to connect it says:
binding to port 500: Address already in use
I have iptables turned off, so I've no firewall. I connect to my wireless router and it's connected to my DSL.
I have to connect to cisco vpn, but I want to use vpnc and not the cisco vpn client. I don't have some previous vpnc session running on port 500.
So, do have any ideas, what does this mean?

[sudarsun]

Actually vpnc is trying to bind to local port "500", which is the default. If you can change the local port to someother free port, your problem is gone for good. There are two ways to do it:

The Complicated Way
1. Open ~/.kde/share/config/kvpncrc
2. Find your chosen profile identified by [Profile_XXXXXXX] ( where XXXXXXX is the profile name )
3. Search for Local port=500
4. Change it to Local port=10111 ( or anyother free port )
5. Save the file
6. Restart kvpnc client.

The Easy Way
1. Open kvpnc
2. Click on Configure KVpnc
3. Click on Profile->Connection Specfic->Cisco
4. Check the checkbox option "Use local port for ISAKMP"
5. Set the value to "local port for ISAKMP" to 10111 from 500 ( you may also choose anyother free port )
6. Click on "Apply"
7. Click on "OK"
8. Try connecting now..