Does anyone know off hand why I'm getting this error message?

[Quantum Radio]

Trying to go live - and Support havent got back yet.. I think it's like
midnight there...

so I wondered if anyone on the list knew what I have done wrong that causes
this to be returned on a perfectly normal .com registration attempt.
..........................
Registration attempt for domainname.com failed: Registration not allowed
under this TLD
..........................

verify_install works fine by the way...

Thanks
Bob