Question : DNS RR set that ought to exist, does not exist.

Interesting one this... All of a sudden I'm getting these messages in Event log, and some of my users dont seem to be given a correct IP address when they log on.  We have a number of DC's and this one in general is playing up.  

Any advice?

Event details-

Source NETLOGON
EventID 5774

Registration of the DNS record '6da3af06-feb2-45ba-9e31-08ed5a3dc5b2._msdcs.I-net-csldn.cityxxxxx.com. 600 IN CNAME NEW_Ixx.i-net-csldn.cityxxxxx.com.' failed with the following error:
DNS RR set that ought to exist, does not exist.  

Answer : DNS RR set that ought to exist, does not exist.

And this one:
GUID Records Are Not Registered If MX Record with Wildcard Character Is Present
http://support.microsoft.com/?kbid=325208