I have setup a DNS for my Global Domain Name, But When i apply the change DNS request of my Domain Registrar, they reject the DNS request that since they discover that My DNS Server cannot find in WHOIS Search
but My DNS Servers is in function since they are using to host the 2nd level domain name, for example, .com.hk
Does any body can tell me how to fix this problem?
>> they reject the DNS request
They shouldn't, just because that's part of their services.
>> since they discover that My DNS Server cannot find in WHOIS Search
That's why they need to ACT in order for your domain to be listed at the roots. That's the exact duty of what a registrar should perform, rather than just taking new sign-ups.
If you have futher question post your real domain name here.