Question : DNS Event 4521

I keep receiving these event IDs in my backup DNS server event log. Im running a 2003 Server, and the data is transfering from one DNS server to the next, I still have these errors.  says.. 9002 attempting to load zone.
I have the Zone transfers set to "only servre listed on name servers" and both name servers are listed within that tab.

Any ideas?

Answer : DNS Event 4521

Here's a link to an EventID.net page discussing this error FYI:

http://www.eventid.net/display.asp?eventid=4521&eventno=8953&source=DNS&phase=1