Can't change password in Kerberos !

[Ta Thai Hung]

Hi all

I installed a KDC named ker1.eab.com.vn successfully with krb5-1.6 version, then I add a principal named hung at EAB.COM.VN. These above step go through smoothly, but there is a trouble when I change password for hung at EAB.COM.VN.

kpasswd 
Password for hung at EAB.COM.VN: 
Enter new password: : 
Enter it again: : 
kpasswd: Connection timed out changing password


After that I come to Window OS computer, and install kfw-3.2 in it. I get the ticket for hungtt at EAB.COM.VN, and change the password. This software show me following error : 
     "requested protocol version not supported"

The same action on other Linux client, and another error :
     "requested protocol version not supported changing password"

It take a lot of time for me to search Internet without any good result. Please help me find out this problem. 

Thank you very much
Hung Ta