Have you tried running 'ipconfig /flushdns' from the command prompt?
It looks like there's a DNS server somewhere down the line from you that is resolving to the wrong place.
Might just be a matter of waiting a few hours for things to update, or it may be an accidental misconfiguration that needs to be brought to attention.
If you really want to get through, you could try changing your network settings to use an alternate DNS. I would recommend
OpenDNS | Providing A Safer And Faster Internet they provide excellent instructions on reconfiguring to use their servers. It's a bit of an extreme step to take for one website, though
