"nameserver not registered in the registry for .com"?

[Steve Maring]

I set up Bind 9.3.0rc2 on my Mandrake box and configured it to resolve
rhythix.com.  I then gave ns18.zoneedit.com and ns19.zoneedit.com
permission to transfer as secondaries and set them up to be so at
ZoneEdit.com.  I then scrounged up the $6.95 to register my
"rhythix.com" domain over at AITDomains.com.  However, when I try to
establish my nameserver config with the registrar, it tells me:

"rhythix.com cannot be modified. Because [my nameserver] is not
registered in the registry for .com"

What does this mean?  It has been a VERY long time since I have tried
to do this.

TIA.

Steve Maring
Tarpon Springs, FL  USA