If you have not updated your DNS you are probably still seeing this forum on its old name servers.

Using martin's suggestion, do this on your windows to flush your dns:
C:>ipconfig /flushdns

But if you have forgotten how to us DOS like me, just switch off your router for about 5 minutes, switch it back on and you will see the forum on it new home. This may not work if you are on fixed IP address.