hi Bram
on the domains zone file there is no record for the root domain. I see you have a Cname for www. Do you also have the IP address you can create a Host record for? the host on the zone edit page would be the @ sign to denote the root domain name.. if not then you may be able to create a URL or Stealth forward via the DNS settings links pointing the host @ at the same target the Cname for www. is pointing to.
thanks
sandy