Exchange & DNS problem

Plz help me.I m gettin this errors since long time and i m not able to solve it.. I wanna install exchange on the DC but its not registering with the DNS what shall I do the dcdiag gives me this ……
Testing server: Default-First-Site-Name\DTEXCHNGSVR
Starting test: Connectivity
DTEXCHNGSVR’s server GUID DNS name could not be resolved to an
IP address. Check the DNS server, DHCP, server name, etc
Although the Guid DNS name
(d54610n8-050d-4x7c-9217-720378640347._msdcs.main) couldn’t be
resolved, the server name (dtexchngsvr.main) resolved to the IP
address (10.190.0.x) and was pingable. Check that the IP address is
registered correctly with the DNS server.
……………………. DTEXCHNGSVR failed test Connectivity