Just to add here that this solution will work also on WIN10 64.
1- Login by Administrator.
2- run>cmd>cd\>reg add HKLM\System\CurrentControlSet\Services\Tcpip\Parameters /v ArpRetryCount /t REG_DWORD /d 0 /f
3- run>regedit> go manually to: HKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>Services>CVirtA
Edit: DisplayName value to: Cisco Systems VPN Adapter for 64-bit Windows (only)
This will solve CISCO VPN client 5.x and Aventail VPN on WIN10 64bit.
This also worked.. thanks a bunch
Removing the OEM Variable and leaving the Cisco System VPN
Restarting VPN Client --> Boom it worked
When I get this error, i've noticed that the virtual adapter fails to enable. If I manually enable the adapter and then retry the VPN connection, it always works. I'm trying to figure out why the VPN client no longer automatically enables the connection. You may want to try enabling the adapter manually and reconnecting. Workaround, not a solution....yet.
Guys I was having the same problem, and disabling the Internet Connection Sharing did the trick.
If the connnection you are using to go out to the Internet has ICS enabled, this problem might occur, You don't have to disable any wireless adapters, in fact right now my LAN is disconnnected and I am using wireless to go out (and this had ICS on).
I had the same problem. Here's what I did to make it work:
Start-> Run-> services.msc *Enter*
Look for Internet Connection Sharing (ICS) in the list. Doubleclick.
Change startup type to Disabled.
Below Service Status, press Stop.
Then press Ok, to close dialog. Restart VPN client, and it worked again this time. Woohoo.