Question : DNS forwarding problem

Need a DNS expert to tell me I am right . . . but will graciously accept wrong.

Have a server 216.200.100.203 which has been hosting a simple site for months, www.kentuckylakeguide.com.  transfered a second site lasst week and seem to be having a DNS problem. I believe it is at my DSL provider not forwarding properly.  The second site is www.oakcrest.org.  A NSlLOOKUP goes to the working kentuckylakeguide.com, but stops at the two NS servers at my DSL provider at 209.249.176.5 and .7 .

Is there anything else that could be causing this, as my DSL provider claims everything is OK?

Good points because I need the second site up!

Server is win2000 SP4 setup as single, standalone domain.  Uses Host Headers to split off sites from single IP address.

Answer : DNS forwarding problem

I don't really agree with that statement. As long as you have the resources to do it and serve your clients also with all the services they need, and everything is well configured, it shouldn't be a problem. What do you think microsoft does?
You solved the problem one way, but the real problem is sill there waiting for you to connect he internal network.
Could be your internal DNS sending out the internal address of your domain, to external (parents) DNS servers, which will be worng information to those outside. If your DNS is configured to update parent DNS servers outside your network, then they could be receiving updates as your internal address (10. whatever), and that will be the address they will give to customers retrieveing your name on the internet.
Check if you have any "." on your DNS forward lookup zone. That could be the problem.