Notice the interval when the errors occur. If it's occuring every hr, then u know is when AD is doing it's consitency check once an every hr or to whatever schedule you set in your NTDSSETTINGS replication. If that's the case, then we are closer. The error is refering to a missing or incorrect SVR records (_ldap and _kerberos) in a sub domain called _msdcs.yourdnsdonamename. Well open your DNS console exapnd yourdnsdonamename in question and make sure that the _msdcs sub domain folder is present with the other subdomain (_sites, _ tcp, _udp, DomainDNSzone folders). Under the _msdcs sub domain folder you should find dc and pdc sub domains. Under dc->Your sites->unders sites->_tcp->in their u should find the two records (SVR) the warning is refering to the _kerberos and _ldap.
If _msdcs sub domain yellow folder(not a grey folder ) is not present then manually create one by right-clicking on yourdomainname zone and select create new domain _msdcs. Rightclick on _msdcs create new domain dc. Rightclick on _msdcs create new domain pdc. Well u got an idea were I am going. The structure is suposed to look like these: _msdcs->dc->_sites-->-->_tcp->_kerberos(0,100,88)service by yourdcname and _ldap (0,100,389)service by yourdcname. If u have two dc-dns then repeat the creation of SVR records (_ldap &_kerberos)for each DC. Repeat the same process of creating for any sites u may have.
*Back at the top make sure u have these structure _msdcs->dc->_tcp->_kerberos(0,100,88)service by yourdcname and _ldap (0,100,389)service by yourdcname. If u have two dc-dns then repeat the creation of SVR records (_ldap &_kerberos)for each DC.
*Back at the top make sure u have these structure _msdcs->pdc->_tcp->_ldap (0,100,389)service by yourdcname. In 2000/2003 AD there is only one DC that has that PDC role. Only one SVR _pdc should be listed here.
*It is possible that some DCs the error is refering are incorrectly register within the DNS or manually fat fingered
