Using Netdiag on my Exchange server - Problems with DC

I run a net diag to find out why I am having issues my exchange server, and I get this pieces of info I ma confused and would like to clean up the network or domain so that I do not run into these issues, can someoexplain what these mean...My domian name is corp.biotone..com....Infact when i logon to the domain controler is is looking for CORP as the domain....
Confused...
DC discovery test. . . . . . . . . : Failed
        [FATAL] Cannot find DC in domain 'CORP'. [ERROR_NO_SUCH_DOMAIN]


DC list test . . . . . . . . . . . : Failed
        'CORP': Cannot find DC to get DC list from [test skipped].


Trust relationship test. . . . . . : Failed
    'CORP': Cannot find DC to get DC list from [test skipped].
    Secure channel for domain 'CORP' is to '\\tactile.corp.biotone.com'.


Kerberos test. . . . . . . . . . . : Skipped
        'CORP': Cannot find DC to get DC list from [test skipped].


LDAP test. . . . . . . . . . . . . : Failed
    Cannot find DC to run LDAP tests on. The error occurred was: The specified domain either does not exist or could not be contacted.

 
        [WARNING] Cannot find DC in domain 'CORP'. [ERROR_NO_SUCH_DOMAIN]


Bindings test. . . . . . . . . . . : Passed


WAN configuration test . . . . . . : Skipped
    No active remote access connections.


Modem diagnostics test . . . . . . : Passed