Not many people are familiar with IPv6 address scheme today. Sometimes, network troubleshooting in Windows Vista and Windows Server 2008 can be cumbersome. These OSs at times tend to give an IPv6 response to a network request instead of the IPv4 answer we're used to seeing. Two things you can do to keep IPv6 out of the picture for now.
Firstly, forces ping to use IPv4 for the request:
Secondly, disable IPv6 functionality entirely (via registry). Set the data for this value to 0xffffffff to disable all IPv6 components (except for the IPv6 loopback interface). This setting also configures the computer to prefer IPv4 over IPv6. Restart the computer for the setting to take effect.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\
DisabledComponents (DWORD): 0xffffffff