The net effect in tapinstall (devcon) is that UpdateDriverForPlugAndPlayDevices returns error code 1450 (ERROR_NO_SYSTEM_RESOURCES).
Apparently ESET interferes with other VPN clients as well: http://social.technet.microsoft.com/Forums/en/w7itpronetworking/thread/f92abbdf-a340-4629-a46c-f186f7c82340 James