unapproved update - where can I find information on this error?

[Bill Child]

named[4843]: unapproved update from [555.555.555.5].4017 for domain.com

Can anyone point me to where I can find some info on what this error means?
The host referred to in the brackets happens to be a win2k advanced server
with active directory enabled, that is set up as a slave to my dns server.
I'm running BIND 8.2.2.P5.

Any useful info would be appreciated!

Thanks

billc at sierraware.com