We are facing this problem on all of our DC's
The DNS server was unable to service a client request due a shortage of available memory. Close any applications not in use or reboot the computer to free memory.
Event ID : 7502. The DNS.EXE is the latest updated version 5.2.3790.4460 . OS : Windows Server 2003 Standard SP2. All patches updated regularly. Please help. Also let us know if there is any updated patch is available or not or this is a know issue ?