DHCP dynamic DNS not working for some windows workstations

[yanivhs]

Hello

I'm running Zentyal 4.0 ( upgraded from 3.4 )
I'm having problems with some of my domain joined windows workstations.

I can get the IP address, a PTR record is created but the host name is not been created in the Forward lookup zone.
When trying "ipconfig /registerdns" the following error is recorded in the syslog:
named[1800]: client 192.168.1.177#59597: update 'domainname/IN' denied

please advice
Yaniv