DNS Operation Refused

Hi,
I currently installed DNS on a Win2K AS with Active Directory enabled.  After the installation, the event viewed keep showing the following 12 messages: (p.s. example.com is that domain that I hold; dnsserver is the server with DNS installed)

1. Registration of the DNS record '48cc9f91-5560-400a-a8de-c790854055e6._msdcs.example.com. 600 IN CNAME dnsserver.example.com.' failed with the following error:
DNS operation refused.  
2. Registration of the DNS record '_kerberos._tcp.dc._msdcs.example.com. 600 IN SRV 0 100 88 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
3. Registration of the DNS record '_kerberos._tcp.Default-First-Site-Name._sites.dc._msdcs.example.com. 600 IN SRV 0 100 88 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
4. Registration of the DNS record '_ldap._tcp.dc._msdcs.example.com. 600 IN SRV 0 100 389 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
5. Registration of the DNS record '_ldap._tcp.Default-First-Site-Name._sites.dc._msdcs.example.com. 600 IN SRV 0 100 389 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
6. Registration of the DNS record '_kerberos._tcp.example.com. 600 IN SRV 0 100 88 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
7. Registration of the DNS record '_kerberos._tcp.Default-First-Site-Name._sites.example.com. 600 IN SRV 0 100 88 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
8. Registration of the DNS record '_gc._tcp.example.com. 600 IN SRV 0 100 3268 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
9. Registration of the DNS record '_gc._tcp.Default-First-Site-Name._sites.example.com. 600 IN SRV 0 100 3268 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
10. Registration of the DNS record '_kerberos._udp.example.com. 600 IN SRV 0 100 88 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
11. Registration of the DNS record '_kpasswd._tcp.example.com. 600 IN SRV 0 100 464 dnsserver.example.com.' failed with the following error:
DNS operation refused.  
12. Registration of the DNS record '_kpasswd._udp.example.com. 600 IN SRV 0 100 464 dnsserver.example.com.' failed with the following error:
DNS operation refused.  

I wonder what causing these problems?  I have enabled dynamic update.  How these records can be registered at DNS automatically instead of adding these SRV records manually?