web page security

i need help. our ompany web page has been changed to this “Dieses Angebot befindet sich zur Zeit im Aufbau!” when we try and access it from interoffice. we are told outside access can still access it fine. what would our problem be? and how canwe go about fixing it? is this virus related? we have nortons installed on all machines and server and auto live update daily. any suggestions would be greatly appreciated.
thanks
steve