Their domain registration has expired. Here is the message on GoDaddy.com whois search:
Status:RENEWAL HOLD
Note: This Domain Name has expired and hence inactive. The Domain Name
must be renewed to activate it. The owner of the Domain Name can
renew it from within the control panel or approach his service provider for the same.
Vandersteen may not even know their web site is down. Hopefully they will pay the small URL registration fee and get their site back up.
