Kerberos and windows problem ...

[daylebo]

same as a lot of people on the forums i too am having a prooblem with
windows taking tickets from a linux kdc ...

i have configured everything properly (at least i think so) but
windows still does'nt login  ...

here is my senario ..
ksetup : 
Machine Realm: XYZ.COM
External Kerberos Realm: XYZ.COM
	Mapping windows at XYZ.COM to guest
	Mapping * to a local account with the same name
	Mapping host/windows.xyz.com at XYZ.COM to guest
	Mapping tom at XYZ.COM to tom

my user is tom ..
i have added a principal tom at XYZ.COM to my kdc ...
i have created a useraccount named tom on the windows machine ...
when i try 2 login it just does'nt .. gives a error like password
might be wrong .. caplock on  ..etc ...
if i do kinit tom from the cmd prompt i get an error saying that it
cannot find any kerberosv4 kdc .. but i still get kv5 tickets for tom
..

this is teh event log generated by windows during login failure ...

Logon Failure:
 	Reason:		An unexpected error occurred during logon
 	User Name:	tom
 	Domain:		XYZ.COM
 	Logon Type:	2
 	Logon Process:	User32  
 	Authentication Package:	Negotiate
 	Workstation Name:	WINDOWS 

any help will be appretiated ..
thanks ...