Invalid DNS Name

Hi all, I just got a situation where the DNS name is a single name EX: blabla instead of blabla.com
I am getting this msg: "The DNS server machine currently has no DNS domain name. Its DNS name is a single label hostname with no domain (example: "host" rather than "host.microsoft.com").

You might have forgotten to configure a primary DNS domain for the server computer. For more information, see either "DNS server log reference" or "To configure the primary DNS suffix for a client computer" in the online Help.

While the DNS server has only a single label name, all zones created will have default records (SOA and NS) created using only this single label name for the server's hostname. This can lead to incorrect and failed referrals when clients and other DNS servers use these records to locate this server by name.

To correct this problem:
1) open Control Panel
2) open System applet
3) select Computer Name tab
4) click the "Change" button and join the computer to a domain or workgroup; this name will be used as your DNS domain name
5) reboot to initialize with new domain name "

but I cannot correct because when following theis procedure, the properties to change it is not available becaue this is the domain controler.
Has anyone been able to fix this problem.
Thanks!: