DNS Problem - Please help

Hi

We installed Windows 2003 Server a few months ago and we're
experiencing issues with it.
Recently we keep on having to reboot the server in order to log in
from the 20 XP workstations connected to it.

The event log shows 4 errors and 1 information, all with the same time
stamp. and it repeats these events roughly every hour.

15:23:55 Source:DNS Event ID: 4007
The DNS server was unable to open zone _msdcs.rjs-network in the Acive
Directory from the application directory partition ForestDnsZones.RJS-
NETWORK. This DNS server is configured to obtain and use information
from the directory for this zone and is unable to load the zone
without it. check that the Active Directory is functioning properly
and reload the zone. The event data is the error code.

15:23:55 Source:DNS Event ID: 4007
The DNS server was unable to open zone _msdcs.RJS in the Acive
Directory from the application directory partition
ForestDnsZones.RJS. This DNS server is configured to obtain and use
information from the directory for this zone and is unable to load the
zone without it. check that the Active Directory is functioning
properly and reload the zone. The event data is the error code.

15:23:55 Source:DNS Event ID: 4007
The DNS server was unable to open zone _msdcs.rjs-network in the Acive
Directory from the application directory partition ForestDnsZones.RJS-
NETWORK. This DNS server is configured to obtain and use information
from the directory for this zone and is unable to load the zone
without it. check that the Active Directory is functioning properly
and reload the zone. The event data is the error code.

15:23:55 Source:DNS Event ID: 4007
The DNS server was unable to open zone _msdcs.RJS in the Acive
Directory from the application directory partition
ForestDnsZones.RJS. This DNS server is configured to obtain and use
information from the directory for this zone and is unable to load the
zone without it. check that the Active Directory is functioning
properly and reload the zone. The event data is the error code.

15:23:55 Source:DNS Event ID: 4007
The DNS server has started.

Any ideas would be greatly appreciated. We're at a loss of what to
do.

Thanks

Graeme.