DNS Reverse lookup not working

Got a bit of an odd situation here. We have 2003/2008 servers with DNS on 2 2003 servers and 1 2008 server (one of the 2003 server will be decommissioned soon hence the 'extra' one)

We have 8 subnets, all served by a single DHCP server which is working fine. DNS updates for each of the subnets-but only updates the reverse lookup for 1 of the zones!

The zone that is working is the 'original' zone, before we added some private ranges to expand the network. DHCP is set to dynamically update DNS always for every zone (sever options) and generally we haven't seen any issues.

Is there a problem running AD integrated DNS on both 2008 and 2003 servers? Or is there another reason why 7/8 of the reverse zones don't update (in fact, they're empty apart from the DNS server entries!)

Seem to have resolved it! Deleted all of the failing zones, and created one 'overall' zone (i.e a 192.168.0 instead of separate ones for each subnet)

Now populating nicely.