seeing bogus error messages after kpasswd

[prashant sodhiya]

Hi,

I've a installed kerberos(5.1.3.3) on a machine having a network interface en0.
my hostname is xyz.com (IP is 9.9.9.0)--this is base IP .
Now i add an alias name to en0 say abc.com (IP is 9.9.9.1).
In my krb5.conf file 
here are my entries:

[realms]
        MY_REALM.COM = {
                kdc = abc.com:88
                admin_server = abc.ibm.com:749
                default_domain = in.zzz.com
        }

Now after this if  execute kpasswd say for a principal prashant.
i see :
Unable to change password.
        Status 0x96c73a26 - Incorrect net address.
Though my password is changed !!
Ny guess why is it happening.
If i change admin_server =xyz.ibm.com:749...things works fine...
I guess if i specify the fully qualified name of my host corresponding to base IP address in kadmin server things works fine...
pls help me why is it so ?
thnx 
Prashant